Switch from cloud server to local server. GSM Hardware code adaptation?

Hey,
I have successfully installed a local server on my RaspPi and reach the Blink administration via my DynDns (xxxxx.ddnss.ch) and port 9443. Furthermore I have forwarded port 8080 from my Fritzbox. Both ports are open.
I want to connect Adafruit feather via GSM (SIM808 module (TinyGSM)) to my server.
The connection to the cloud works with this setup.
I specify my DynDNS server and the port so far:
Blynk.begin(“blynk_key”, modem, web.vodafone.de, vf, vf, xxxxx…ddnss.ch, 8080)
Apparently this is not enough?!

Regards
Felix

It’d difficult to know without more information.

Is the

surrounded by quotation marks in your actual Blynk.begin command?

Pete.