Edit:
Due to expired certificates the handshake between client and server caused the failure. Now, everything works as expected.
Regards,
Matthias
Hi Mellow,
thanks for your reply! I was able to access the WebUI from outside my network but the router wasn't operating on the latest firmware. I updated to RUTX_R_00.07.00 but the problem still persists. I'll send you the troubleshoot file via pm. If there is any known issue with port forwarding on the latest firmware I will downgrade to _02.06.1 (but this will reset the config).
Regards,
Matthias