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!

An error has occurred Code: 0xC004F050 Description: The Software Licensing Service reported that the product key is invalid
Error Causes
Valve has officially announced that Steam Deck will be compatible with Windows 11 despite TPM 2.0 Microsoft requirements.
From the beginning, Deck was announced like a mini handheld PC device. Powered with new Steam OS 3.0 based on Linux. However, besides out-of-the-box OS it was also stated that Deck will be a personal device meaning that other PC-based operating systems could be installed on it and even run your typical applications in it.
Since Microsoft announced Windows 11 hardware requirements, specifically the TPM 2.0 requirement many users voiced concern that Steam Deck will not be able to connect to Windows 11
TPM 2.0 is something that Microsoft requires for every internal and hardware component that is to connect on a Windows 11 device. This is to ensure that only trusted devices would be included in the array of a PC setup and avoid any problems like malicious hardware injecting software into a system.
This would also minimize the compromise Windows would have, as unverified or untrusted devices connect to a Windows PC.
However, Valve and AMD are ensuring us that Deck will not have any issue connecting to a PC running Windows 11 or even if you wish to transform Deck itself into a Device running Windows 11.
Error CausesThe 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.
“Windows is unable to reach your company’s activation service. Please connect to your corporate network. If you are connected and continue to see the error, contact your system administrator. You can also click on the error detail to find the exact error. Error code: 0xC004F074.” “Activating Windows(R), (Key hash)… Error: 0xC004F074 The Software Licensing Service reported that the computer could not be activated. No Key Management Service (KMS) could be contacted. Please see the Application Event Log for additional information.” “Error 0xC004F074, SL_E_AUTHN_MISMATCHED_KEY, The Software Licensing Service reported that the key is mismatched.”To fix the Windows 10 Activation error 0xC004F078, you have to use the correct key for your type of Windows copy or use Command Prompt to reinstall the key or you could also try running the Activation troubleshooter.
The Gardening Enthusiast toolbar is another product that is advertised as a helpful addition to your browsing experience when it is really nothing more than the software you should remove as soon as possible. It is touted as a toolbar that will provide you with a lot of useful gardening tips. That is the hook to get you to install it. But, in truth, the only thing that it does is provide you with links to popular gardening websites that you can easily find on any search engine.
When installed the extension will change your default search engine and home page to MyWay.com
While browsing the internet with this extension you will see additional sponsored ads and links throughout your browsing session.
Anti-virus applications have marked this extension as a Browser Hijacker and are therefore marked for removal. While not considered malware, the fact that many users find it to hinder browser performance has led to its detection and flag for optional removal.
MyScrapNook is a browser extension for Google Chrome that allows users to easily find scrapbook templates, layouts, and graphics. This extension requires the use of Adobe Flash Player and does not work with Chrome’s built-in flash player.
When installed MyScrapNook will change your home page and default search engine to MyWebSearch.com. It will also inject unwanted ads and sponsored links into your search queries. This extension has been marked as a Browser Hijacker by several anti-virus applications and is recommended to remove it from your PC.
From the Author:
FREE scrapbooking templates, layouts, and graphics! Get creative with tons of FREE scrapbooking features. With MyScrapNook, you can make beautiful, custom scrapbooks — with just a few clicks. Let us help you capture the memories with FREE scrapbook templates. The MyScrapNook extension offers convenient web search and features from the Chrome New Tab page.