This is a problem which you will find you encounter with increasing regularity in future - More and more ISPs are now blocking and my understanding is that in DE the situation will soon be similar to that in the UK - All ISPs will be required to block streams which include copyright material. - I suggest becoming familiar with Android STBs which probably represent the most versatile solution - It is easy to install a stand-alone VPN or one of the increasing number of IPTV apps on which you can integrate a VPN of your choice.
You can try:
Connected with VPN and try to start the IPTV if is works with wifi ( Free VPN user cant connected mostly, you need a paid subscription from VPN provider )
Check with mobile connection LTE or 3G if you can connected or not
VPN subscription ( With Wireguard )
VPN router ( Better with Wireguard VPN option )
Android Box ( Is easy setup and have a lot VPN apps )
Like mag box without android ( you must put it from router to vpn router )
Wireguard is very faster as open vpn connection.
Example ISP Who begin to start :
Vodafone operator (Unitymedia) From Germany