I suddenly got the following error message when trying to sync from Office365 via Davmail. It has worked perfectly until now.

Syncing lrs_contacts
Syncing lrs_calendar
error: The server returned something vdirsyncer doesn't understand. Error message: InvalidXMLResponse('Invalid XML encountered: mismatched tag: line 24598, column 441\nDouble-check the URLs in your config.')
error: While this is most likely a serverside problem, the vdirsyncer devs are generally interested in such bugs. Please report it in the issue tracker at https://github.com/pimutils/vdirsyncer/issues

So this is a show stopper to me. Is there something I can do to solve the problem?