It looks like subscribing to Yhteyspiste supplemental service has failed.

Please contact the customer service to make sure that Yhteyspiste has been subscribed for and for the correct phone number. For example, could Yhteyspiste have been mistakenly activated for your mobile phone sim and not your router sim?

While sorting this out, you can try forcing your router to use UMTS / 3G network and APN prointernet. This APN will give you a public ip address on all Telia mobile services, but only on GSM and UMTS networks. APN prointernet is not available on LTE / 4G nor 5G networks.

After you have sorted the subscription issue out, you can reset your router's network selection to automatic or LTE / 4G only and change the APN back to opengate.

Yep, I was already in contact with Customer service to check that my configuration was correct, which they confirmed. However, due to your response I reached out to customer service a second time, and they confirmed your suspicion - opengate was not at all setup for my subscription (misstake from Telia's side).

When I now configured the APN I instantly got an IP. No reboot required. Problem solved.