Sync problems and users disappeared from user monitor

[Nicklipov]

Hello!

I have a problem with syncing my App.
The problem appeared about month ago - sometimes adding a new row took about 180-210 seconds.
Today the problem became bigger - every “add row” operation take 180-210 seconds.
My users make about 200-300 new rows per day…

I’ve tried to delete old rows (about 8000 rows) and some app functions, now the app’s goal only to add rows in two tables.

I receive two types of errors:

1. “Error: Data table ‘the_name_of_the_table’ is not accessible due to: The operation has timed out.”
2. “Unable to add/edit/delete row in table ‘the_name_of_the_table’. → Too many users are attempting to modify the spreadsheet ‘DocId=some_doc_ID’ at the same time. Please try again after a few minutes.”

My offline/Sync options:
Sync on start - off
Delayed sync - off
Automatic updates - on
The app can start when offline - on
Store content for offline use - off
Server caching - on
Delta sync - on

Do anyone know - what should I do to sync faster? Is there is any way to reset changes to every devices?

Also a lot of users have disappeared starting from December.
Actual amount of users should be about 160 - 180 users (most of them are “guest” users).