I think I have the same problem with a setting up a new Apple Watch with a Multisim as other people have been having recently.
I have a new 4G Apple Watch Series 9, and an iPhone 12. Both are up to date. I have reset network settings and restarted both devices. I'm still getting the 'not eligible' error.
![](https://uploads-eu-west-1.insided.com/tmobile-nl/attachment/fc5112c8-ed01-4d70-9f57-02bcf036502d.png)
The last digits of my phone number are 8899