Outlook 2010 no longer synchronizes with iCloud

I recently bought an iPhone and want to sync with Outlook 2010 via iCloud (App). At first it worked and after I installed and uninstalled some more applications (to test the sync with the iPhone) the synchronization suddenly stopped working. And I can't get it to work even after intensive internet research.

When I click on "Mail, Contacts, Calendar and Tasks" in the iCloud app and click on the "Apply" button I get the following error message: "Your configuration could not be started due to an unknown error. (0x800706ba)"

After clicking the "Try again" button, the following message appears "Configuration cannot be continued because Outlook has been set up without a default profile. Check your Outlook settings and try again."

Can anyone help me? Thanks in advance.

Can Outlook work fine with iCloud for Windows? Please check this article and see if it could works. https://support.apple.com/en-us/HT204571