The Get Add-Ins button does not work

I have already discussed the problem with support. He recommended the forum to me.
I can't get add-ins in Outlook 2021 for Mac because the corresponding button is grey.

I have tried all privacy settings. Connected experience is enabled. Reinstalling did not help either. Neither did the Outlook app from the app store.

I then tried creating a new profile. That doesn't work either. Although the old profile is deleted, the mails are still displayed.

Support wrote:

If this is the case, the new profile we created should be loaded, not the old one. If it doesn't load the new profile we've created, it could be a problem with your Mac user itself. 

As of the legacy version, Privacy, New Profile, and Reinstall Microsoft Office 2021 don't work to enable the Get Add-ins button in your Outlook for Mac. I recommend you post this issue to our Outlook community hub using this link: https://techcommunity.microsoft.com/t5/outlook/ct-p/Outlook  Our Outlook tech community support is experienced in troubleshooting Outlook UI issues. They will respond within 24 hours, subject to availability.  In addition, I recommend that you contact Apple support and ask them to help you create a new Mac user profile on your device. Once created, reinstall your Microsoft Office 2021 and see if it fixes the issue. 

Can anyone help me to solve the problem?