I have a new Dell desktop computer, with Windows 10 Pro installed, Version 1909 fully updated. I installed a fresh copy of Microsoft Office 2016 and everything worked perfectly. I then opened and added a pop3 email account to Microsoft Outlook which also worked great. I then imported from a previous PST file all old, new, deleted, etc. files and contacts into the new profile which I had just created. That worked very well and things worked great - until it didn’t. I added another email account and after that new addition - the emails worked perfectly for less than 10 minutes - then the send/receive stalls - both accounts send but do not receive and I get Error Code 0x8004210A which means Microsoft failed to establish a connection with the mail server. I uninstalled that second email account but it made no difference.

I then researched the error code and none of the possibilities provided were appropriate other than the possibility of “user profile damaged”. I then created a new user profile - repeated all above steps and again it worked for a day - then reverted to lasting less than 10 minutes after a reboot. I also went into Control Panel - email accounts - and ran tests on the account and it works perfectly and also ran it in Outlook’s safe mode - again - it worked perfectly.

I know all email settings are correct for pop mail. I have many computers and they are all configured exactly the same with the various port settings and security settings plus I double checked the settings with the internet provider.

When I used Microsoft’s on-board PST tool “ScanPST” - it states there are errors - it shows they are repaired - but after running the tool again, it still shows there are errors.

Again - if I restart the computer - Microsoft Outlook works perfectly for less than 10 minutes - then stalls out as described above.

I am now stumped - can anyone help?