Why can there be no connection to the Internet after losing and resuming the signal on the router with mobile Internet?

Question

Computer networks

There is a device, a logger, which is connected via a LAN cable to a router with mobile Internet. The logger is simply on some kind of microcontroller, it sends information to the cloud. Tplink router.
And periodically there is a situation that the logger stops transmitting data, does not see access to the Internet. At the same time, the router writes that there is Internet and, for example, I check it from a PC and it really is. I noticed that this happens with some communication failures, after a failure, the router gets access to the Internet, and the logger does not see it point-blank. Now it is solved by daily reboot at night.
Suggest possible causes of the problem to try to solve.