NextCloud doing something to Internet router

I have NextCloud on a VPS. I access the server via a web url and also upload from the desktop client. Everything seems to be working great except for every now and then it’s like NextCloud gets blocked by the router.

I can still access any webpage, except for NextCloud or the desktop client. When accessing via the webpage I get a connection time out error and on the desktop client I get a time out error.

However if I use my phone or an alternate service (we have a backup internet) I can connect perfectly fine. I called the ISP they refreshed the modem and then everything worked.

Then today the same thing happened and I was in the middle of a project, so I switched the computers over to the backup internet, well 5 minutes later it became inaccessible there too.

Did a reset on both modems and it came back up.

Has this happened to anyone else? It’s as if the router is just randomly blocking the site.

have you checked your brute-force settings?