@sulliwane this is not exactly the same problem. You should refer to issue #3 as @rfc2822 said in his last comment.
Google Play license verification check error
since updating from version 1.5.2-gplay my sync stopped working and I get a notification saying the Google Play license verification has failed.
I am currently running lineageOS without google play and I’ve bought the application from the Play Store (on my other phone that I use exclusively to download apps and updates from the store with my google account).
If I roll back to version 1.5.2 everything works again, did anything change since version 1.5.2? Any help would be really appreciated.
For devices without Google Play, please use the DAVdroid OSE version from F-Droid. The Google Play version checks its license.
License check was for testing purposes only and will be removed in the next version. In the meanwhile, please use the F-Droid version (or compile DAVdroid from the sources).