Errors sending TCP packets to Wireshark?

Question

Wireshark

I'm writing a small bot that periodically makes a mailing to the server, each "message" is sent with a delay of about 1-2 seconds.
Recently, an incomprehensible problem has arisen - messages do not reach the server, while there are no errors on the client, as well as on the server. But Wireshark shows strange messages like "TCP Window Full" followed by "TCP ZeroWindowProbe" and "TCP ZeroWindow".
What causes this and how to fix it?