Why does not see the server on the raspberry pi?

Question

Raspberry Pi

Good day to all!
I decided to make cloud storage using Seafile on "raspberry".
Seafile installed and configured, forwarded ports on the modem, went to the address in the browser and everything works!
BUT ... installed the client, entered the address and then the trouble. It shows all libraries and files on the server, but it fails to upload new ones or synchronize to a folder, because it cannot receive a response from the server, why is that?
please help me to understand the problem
If you connect to the client via LAN, then all the rules work.