Thursday, December 3, 2020

How to fix Outlook desktop app account problems with or blocked, stopped, not working, authentication problems

Recently, my Outlook desktop app client started to have authentication problems for my / emails and I though initial it was due to outdated setting see below. But it was not, that was not the cause of the problem. 

Update Thu 11-Feb-21 9:00pm - How to check Outlook desktop app account connection problems with or blocked, stopped, not working, authentication problems

Seems using my Kasperky VPN has cause spam and fraud rules to triggered on Microsoft mail servers. So any IP address using this service are blocked.

MAIL FROM from SMTP Server : 550 5.7.1 Unfortunately, messages from [] weren't sent. 
Please contact your Internet service provider since part of their network is on our block list (S3150). 
You can also refer your provider to 

(I wish they had a application level authentication token that would get around this.)

However, if you are connecting from different countries or IP addresses (if you are a mobile worker for example) you will like trigger the following warning. is complaining of suspicious activity and has temporarily blocked access.  

Solution: Login into or email via your browser and then your Outlook desktop client will work. 

Double check these new server settings as well. 

There are new server settings, and available here for reference :

New server settings

IMAP Server:

Port: 993

Encryption: SSL/TLS

POP Server:

Port: 995

Encryption: SSL/TLS

SMTP Server:

Port: 587

Encryption: STARTTLS

Goto E-mail accounts and edit your existing connection to use the above setting, below is for POP/SMTP settings. Change to new setting in above table

Use TLS, if you cannot choose both under "More settings....."

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