Google Tasks not syncing (events do) on the phone

Question

I have a OnePlus One running CyanogenMod 12.

I started using tasks within Business Calendar 2 PRO app heavily. They synchronize using google tasks. So I can see my tasks in google calendar. This works well with my Nexus 7 2013 tablet and PC and worked well with the phone too. The phone recently stop synchronizing correctly and does not want to work again.

_{Screenshot - Sync (Click to enlarge image)}

I noticed that arrows stay present after trying to sync the Calendar. First they wiggle instead of turning awkwardly and end up staying there. The events get synced, the tasks not.

I also have a "Sound Search for Google Play" syncing problem, but I turned that one off for the reason so that it does not interfere.

I have no idea what to do. Once I had a similar problem with Google Keep and I managed to find a card that was causing some db problem on google site - I removed it and synchronized and it started working again. But I could not see anything interesting in the logs this time.

Answer 1

Following instructions worked for me:

1. On my HTC M8, I went to Settings → Apps → found the Business Calendar 2 PRO app (it is listed as "Business Calendar") → cleared Cache → cleared data of the app (did not need to uninstall/reinstall).

2. I went back to the Business Calendar app on home screen and it wanted to set up as new but my calendars and most of the data synced very fast (I think it is because I did not uninstall the app).

3. I had to again choose my tasks' Gmail account and then Tasks were synced correctly!

   Also, check your other settings for calendars and others. I have another Android phone so I use it to confirm that settings match. The tasks on other phone were syncing fine on Business Calendar.

Answer 2

I fixed it by going into the "TASK LIST" Tab in Business Calendar 2 and remove the google Account in the bottom. After a little while, when the Tasklists disappeared as well, you may just click on the google Account again and a window will pop up to grant the app permission to access the Tasks.

Answer 3

Well in the end, I managed to fix the problem by

1. removing my google account from the android device.
2. Then I opened up Business Calendar and it was still showing the dead task list on the device although the calendar and other task lists were not present.
3. I removed the traces of the tasks and list which was dead and then I think I reinstalled Business Calendar (not sure).
4. In the end I readded my google account to the device and opened up Business Calendar and it was working again with the sync.

However, the arrows at the calendar are still there. But everything seems to be working.