Hi, I was able to take a peek at the logs for your app using the request-ids in the image you provided. All of your errors stem from the connection to MongoDB having issues every once in a while, and when that happens sync will retry for about 1-2 hours before giving up, emailing you, and presenting you with this button in the UI.
Unfortunately, this is why we reccomend starting on at least an M10 cluster for any production or pre-production app. The reason is that the shared tier clusters have limited observability (fewer metrics are visible in the UI), various forms of rate limiting occuring which could be the cause of your issues, and generally more suceptible to the noisy neighbor issue.
Your best bet will be to terminate sync, upgrade to an M10, and re-enable sync. I suspect you will stop running into this issue entirely.
I hope this helps, and let me know if you run into any issues after upgrading and I would be more than happy to continue looking into it (but I strongly suspect that you will not given this is almost always just a symtom of being in the shared/free tier).
