Just moved from Vodafone to EE mobile broadband and have the Vodafone issued Huawei CPE Pro 5G router.
Switching over was fine for all devices except the NowTV stick. It could get a WiFi connection but the Internet connection failed every time. I could see on the router that it had an IP address. I reset the stick to defaults and all other devices were fine on either connection. All other pieces of the home network setup were the same.
Due to having an IP but no connection I suspected the problem was something in the DNS infrastructure of EE. Changing the default DNS server settings on the router to Google DNS fixed the issue.
Specific fix for the Huawei CPE Pro - the default DNS settings are only visible in the APN setup of the router. So you have to:
create a new default APN profile
Use the standard EE APN details available online (eesecure/secure/PAP/everywhere)
only use the IPv4 setup (the combined IPv4 & 6 didn’t work).
I used Google public DNS servers (188.8.131.52 & 184.108.40.206)
The same fix might work on other routers but certainly for any issues with the stick failing to get an internet connection (but getting WiFi) is likely to be a DNS problem.