How to find the cause of the speed drop in Mikrotik?

Question

Mikrotik

Faced the problem of a sharp drop in the speed of traffic exchange in Mikrotik, the problem began to appear a few days ago, before that everything worked fine for 2 years.
The bottom line is this - you start downloading, the speed is maximum, after 20-30 seconds the router resets the connection (as if restarting the interface) and so on again and again.
It manifests itself both in internal traffic and in external traffic. The logs are crystal clear, even nothing in the info.
I am attaching a short screencast - https://take.ms/9o1nx
Router Mikrotik hap ac lite

Answer 1

Recently faced the same problem.
At the same time, I did not make any changes in the settings, I did not change the network infrastructure. A month ago, the speed was confidently stable in downloading torrents, and a week ago it started dropping to zero and rising by 20% of what it was.