VS2019 Online Extensions list is empty. Then full. Then empty again

Question

A colleague is having a bizarre problem with Visual Studio. I am literally watching this happen live while we're on a Teams call and she shared her screen.

In Visual Studio She goes to

Extensions >> Manage Extensions >> Online

And sees this error message

A connection to the server could not be established because the following error(s) occurred:

An error occurred while sending the request. The underlying connection was closed. An unexpected error occurred on a send. Unable to read data from the transport connection. An existing connection was forcibly closed by the remote host.

Here is the weirdest part. She will click around elsewhere in Visual Studio without making any changes (e.g. we were looking at things like Tools >> Options >> Accounts but changed nothing) and come back and suddenly all the extensions will appear.

Then, she'll go away and come back to it and they'll disappear again with the same error message

We cannot seem to find any rhyme-or-reason as to why this would happen. We tried disabling all firewalls she has (Windows Defender) but it made no difference.

Any idea where I should look?

(I did find this question but it does not seem to apply

vs2017 cannot browse online extensions)

Answer 1

Try these:

1) close VS, delete the folder C:\Users\Administrator\AppData\Local\Microsoft\VisualStudio\16.0_xxx, then restart VS to test again.

2) not sure if this is a problem of DNS. Please check this document. Or you could try to fix your DNS.

3) close VS, open C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\devenv.exe.config and then add these:

<system.net>
  <defaultProxy useDefaultCredentials="true" enabled="true">
    <proxy usesystemdefault="true" bypassonlocal="true" />
  </defaultProxy>
  <settings>
    <ipv6 enabled="true"/>
    <servicePointManager expect100Continue="false" />
  </settings>
</system.net>

Then, save it, restart VS to test again.

4) update VS2019 if there is any new release versin.

Answer 2

I found the answer on the Visual Studio forum:

I found the issue, it was because the "The Program worked in earlier versions of Windows but won't install or run now" option was set. This check box is in Program Compatibility Troubleshooter of devenv.exe in \Microsoft Visual Studio\2019\Professional\Common7\IDE folder.