I also had this problem, I found a solution without do a factory reset.
The app in question is TestService.
First you have to clean the directory /data/clipboard, delete everything in it with root explorer. After that, go to...
I think I managed to find a workaround which doesn't involve a factory reset:
Settings -> System -> Reset options -> Reset app preferences (this doesn't affect apps data)
Settings -> Apps & notifications -> See all XXX apps -> (3 dots in the...
The link you gave goes to a Not Found error. Perhaps post the name of the app as well?
That's weird, I've checked and it does work for me in the UK. Maybe it's only available in some locations.
The app is called Push Notification Fixer, ther...
Personally, the only method which completely resolved the issue was to install this app called Push Notification Fixer and reduce to the minimum the heartbeat-interval number
Hello! It works also for me =)