Hi there:
You need to set an enviroment variable called P4TRUST, which points to a file on disk
Usually p4trust.txt or .p4trust
eg P4TRUST=/app/Data/.p4trust to your docker compose enviroment variables
Then whith that trust fille add the fingerprint of the server to trust in the right format like this.
IPAddress:Port=**++**:FINGERPRINT
eg my made up ip address
113.123.1.7:1666=**++**:A1:B2:C3: rest of fingerprint etc
Note the : seperating the start of the fingerprint.
Good Luck!