Error 421 is a common SMTP (Simple Mail Transfer Protocol) Outlook error message. MS Outlook is one of the best and popular email applications widely used by PC Windows users for sending and receiving emails within and outside workplaces.
It is most commonly used in offices by professionals for faster communication.
This error may occur while sending and receiving emails on the server. The error 421 messages is displayed in either of the following formats:
“An unknown error has occurred: Server error 421”
"Could not send your message. Error 421"
421 4.2.1 : (DYN:T1) http://postmaster.info.aol.com/errors/421dynt1.html
421 4.3.1 Out of disk space for temp file
421 4.3.2 All server ports are busy
421 Downstream server error
421 Fork failed
421 Greylisting enabled, please try later
“An unknown error has occurred. Subject ‘Testing’, Account: ‘pop.charter.net’, Server: ‘mail.charter.net’, Protocol: SMTP, Server Response:
’421 Message rejected’, Port: 25, Secure(SSL): No, Server Error: 421, Error Number: 0x800CCC67”
Error CausesSome common causes for this critical Outlook error are:
This is a critical Outlook error that should be resolved timely. If you delay, it may cause you a great deal of inconvenience.
The error code 421 hampers your ability to access your email account, send and receive emails, add new contacts, view emails, calendar entries, and journals. In other words, it just brings your email activities to a standstill locking you out of the account.
To resolve this error code on your system, you don’t always have to hire a professional or call the network personnel to do the job. It may be a critical error but the good news is that it is quite easy to fix. Even if you don’t have technical expertise, you can still repair it.
Here are some of the best methods to repair this issue on your system:
Try changing your server settings. Here set the inbound connections limit at the maximum limit.
After the process is complete, try accessing your Outlook email account again; if it works, then that’s great the error 421 is resolved. However, if it doesn’t, then the problem could be related to viral infection.
If the cause of the error is PST files corruption, then not only will you be locked out of your email account, you are also at risk of losing all the data stored in your email account.
However, the best way to resolve the error and ensure full data recovery is to download a reliable PST repair tool. By running a PST repair tool on your system, you can resolve the error 421 right away. It recovers your data, repairs corrupt and damaged PST files.
If viral infection and Trojans are causing the error 421 to pop up on your system, then it is recommended to download and scan your PC with Restoro.
This is an advanced, intuitive, and user-friendly PC fixer. It is not just an antivirus but also a system optimizer and a registry cleaner.
Unlike common antivirus software that only removes viruses and simultaneously slows down the system’s speed, Restoro removes all types of malicious software on your PC including malware, spyware, Trojans, and viruses, and also boosts the speed of your PC significantly.
It is safe, easy to operate, and a quick fixer. It is compatible with all Windows versions.
Click here to download Restoro and resolve error 421 today!

Error CausesCON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9When you rename or create a folder or file using the reserved words given above, you could encounter an error that says, “The specified device name is invalid”. This occurs since these words are Windows system reserved words that you can’t use, unlike any other words. Thus, if you have a folder or file which contains any of the reserved words on another computer that runs a non-Windows operating system and you try to copy or rename it Windows, then it’s no wonder why you’re getting this error message. In such cases, you can always click on the Skip button to stop the operation. However, if there are various folders or files, you can just use the Command Prompt to carry out the task. All it takes is a simple command that will get rid of the folder as well as the files in it. How? Refer to the instructions given below. Step 1: Tap the Win + R keys to open the Run utility. Step 2: Next, type “cmd” in the field and then tap Enter to open Command Prompt. Step 3: After opening Command Prompt, execute the following command:
rd \.file-folder-path /S /QNote: The “rd” command will remove the directory or the folder while the “\.” command will select the current computer. The “/S” command, on the other hand, helps you in removing all the sub-directories and the files that are in the CON folder. The “/Q” command is not really mandatory since it helps you remove everything silently without any confirmation message. For example, if you have a folder named “CON” located on your Desktop, the path will be like this “C:/Users/<username>/Desktop/CON”. In this case, the command should be like this:
rd \.C:Users<username>DesktopCON /S /QHowever, if the error pops up for a whole different reason, you could use the following command instead to remove the reparse point extended functionality. Once you’ve entered the given command below, you should now be able to delete the file.
FSUTIL reparsepoint delete C:Users<username>DesktopFileName DEL C:Users<username>DesktopFileName
The Motitags toolbar browser add-on was created by Mindspark Inc. and is compatible with Internet Explorer and Mozilla Firefox. It claims to enhance users’ Internet browsing experience by enabling smileys within popular email clients such as Gmail, Yahoo!, AOL, and Outlook Live. While such added functionality may seem useful, Internet users should be aware that this browser plugin is categorized as a Browser Hijacker due to its behavior.
When installed this extension changes your default search engine, the home page, and new tab to MyWay.com, and while installed it gathers user browsing data and sends it back to Mindspark servers. This data is later used to inject additional unwanted ads into the user’s browser search results.
diskpartStep 5: Afterwards, type in either of the following commands to help you in either listing all the Disk connects or all the partitions on those disks formed.
diskpart or list volumeStep 6: Next, you need to select any of the two given commands below depending on the list you entered on the previous step.
select disk # or select volume #Step 7: After you enter the command, it will select the Disk or the Partition you want to select. Now you have to type and enter the following command to clean your drive.
cleanStep 8: Now enter any of the two following commands.
list disk or list volumeStep 9: Then type the next command below to create a specified partition.
create partition primaryStep 10: Once done, type in the following command to select the newly created partition.
select partition 1Step 11: Next, type the following command to mark the selected partition as active.
activeStep 12: Finally, restart your computer to successfully apply the changes made and then see if it has fixed the problem or not.
The first thing that would pop into my mind is that I have lost tons of work and that something in my hardware has gone very wrong and it is dead. Luckily that is not the case and this error means that due to Windows update drivers were not properly transferred due to some compatibility issues, maybe it was a corrupt update file, etc. Of course, the reason could be hardware malfunction as well, but if everything was working fine before the update, it is a software issue, and I must say it is a common one and fixable. Please keep reading this guide in order to fix the Device not migrated error.
Find device inside device manager, right-click on it, and choose properties. Go to the events tab and make sure that the device has migration issues.
You have now 3 options for updating the driver, you can do it manually, automatically, or with the driver installer. We will cover all 3 options so you choose which one best suits you.
OPTION 1: Manually.
Close the Properties tab, go to the device manufacturer website and download the latest driver, if there are no drivers there, the only executable installer for the device skip this step and try the other 2. After you have downloaded the driver package from the website, right-click on the device and choose update driver.
Now navigate to the folder where you have downloaded your driver package and update the driver. Reboot your system.
OPTION 2: Automatic update.
Close the Properties tab, right-click on the device and choose to uninstall.
Once the device is uninstalled, restart your system, and Windows will automatically search and install the latest driver for the device.
OPTION 3: Via driver installer.
If you have downloaded .EXE or executable driver installer from device manufacturers web site try installing it, if the installation fails, try using compatibility mode for the installer. Navigate where the installer is located, right-click on it, and choose properties. Go to compatibility TAB and try installing it with administrator privileges in Windows 8 mode.
Reboot your system after this step.
This should solve the issues, however, if the issue still persists, follow the next steps.
In the command prompt type in: sfc /scannow and press ENTER.
The scanning process and repair of files will take around 15 min. Leave it to finish completely, do not restart, work on the computer or shut it down while the process is active, and only after it is finished reboot your system.
Go to the Windows update tab and click on DOWNLOAD or click on check for updates for the latest Windows fix.


In the run dialog, type control panel and press enter to enter control panel, locate recovery and click on it.
Inside the recovery screen click on Open System Restore.
Choose a date when everything was working in order, the best bet is the date before Windows update and roll it back.
Click on date, and then on next.The drivers for this device are not installed. There are no compatible drivers for this device.The problem here tends to no longer allow specific Bluetooth components to properly communicate with your Windows 10 operating system. It also affects laptops that do not have native Bluetooth support; therefore, the manufacturer installed a dongle on the inside to deliver the service. This is not the best way to do things because native support is always better. On the other hand, maybe you’re using a Broadcom USB Bluetooth dongle that is acting up, and as such, the error is showing. Below are solutions provided for this particular error and how to eliminate it.
“The file magcore.dll is missing” “MagCore.dll cannot be found” "Cannot find [PATH]magcore.dll" “This application has failed to start because MagCore.dll was not found. Reinstalling the application may fix the error.”
Error CausesInstaling and removing applications from your Windows can sometimes leave some traces that are unpleasant and can cause annoyances. One of these annoyances is the program in the startup section of the task manager.
If you ever opened task manager and went into the startup section trying to disable some of the startup items on your Windows boot there might be a chance that you have experienced and seen a program without any icon or information about it just sitting there.

This is due to some applications being removed from the system but for some reason, it still shows itself in startup and it is quite annoying. So here we will show you how to get rid of this annoyance so your startup is clean again without junk in it.
The first thing of course is to open the task manager itself and navigate to the startup tab. Inside the startup tab right-click on the column header and tick or enable Startup type and command line. Now you will see the location of the supposed file (that is missing or you could just go there by right-clicking on the item, but here it is greyed).

99% of the time startup type will be registry since the file is missing, if it was a file fix would be just to simply delete the file in the folder but since it was installed and not properly removed registry key is still present but the file cannot be found. After confirmation that the file is indeed missing and that the startup type is registry open the registry editor by typing Regedit in search and pressing enter.
Inside Registry editor navigate to: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run. Inside on right part, you will see all auto-start entries added by installed applications.

Locate one that is causing issues by comparing its path with the path inside the task manager command line and delete the key. Once the key is deleted right-click on RUN on the left part and choose HKEY_LOCAL_MACHINE to quickly jump on that key location and repeat the process of key deletion if needed. HKEY_LOCAL_MACHINE will delete startup entry for all users and sometimes entry will not be present here since the application is not installed for all users or there are no other users on the machine.
After the procedure is finished, reboot your systems in order to apply changes.