No connection to Windows server 2022

I installed mosquitto on a Windows Server 2022, hosted by Strato.
I can not connect to mosquitto from outside.
On the server mosquitto works, I can use mosquitto_sub and mosquitto_pub as well.
I made the same changes on defender, as I did when I installed Filezilla ftp-server.The ftp-server is reachable from outside. I added mosquitto to the allowed apps in defender.
An installation of mosquitto on an internal PC (Windows 10) workd well an is also reachable from outside my local network (via LTE).
Any idea how to solve the problem ?


Hi kdherr,

By the description I donĀ“t directly see a problem.
Opening the ports via defender would also have been my first guess.
What are the exact changes you did on defender?