Synergy: does the SSL certificate not exist?


I have installed Synergy v1.8.8 on my Ubuntu. It works well as a server until the next reboot. Once I restart the machine, it shows the following errors:

(2020-02-14T11:58:08) ERROR: ssl certificate doesn't exist: /.synergy/SSL/Synergy.pem
    /build/synergy-iliE6X/synergy-1.8.8-stable+dfsg.1/src/lib/net/SecureSocket.cpp,617

The only solution I found so far is to reinstall Synergy. Then it works fine (until the next reboot).

How can I fix it perfectly?