Hi,
I am back in Sweden for a longer period. Last times I was here I didn’t bother to make tests.
So I am on a FP4 with CalyxOS (newly installed 7.2.2.0). I am roaming in Sweden. Data and sms work, but I cannot call or receive calls.
My operator thought that the problem came from a too old SIM-card, so they sent me an eSIM, which didn’t change anything. I am not allowed to use Telia or Telenor, so I just tried 3 and Tele2. Neither work. I would like to find someone with a sim card from a Swedish operator to make some tests. And I would like to find someone with a FP4 who could try roaming in Sweden with another Swiss operator on the same Swedish networks (Tele2 and 3). I wonder if the problem is with all FP4 users on all networks, or only on Tele2 and 3; or only for (some?) roaming users. I wonder if the fact that I am using calyx makes a difference.
Fairphone users seem to have the same kind of trouble in Australia: 🇦🇺 3G network closure - Australia - #142 by IainM (there is a link to our discussion there, but not the other way around) and with one operator from Denmark in Sweden: No VoLTE when roaming - #4 by bonnel
Looking around (but all of this is above my paycheck), it seems that the problem is with VoLTE roaming specifically and not with all operators. I found this page from the UK operator 3 saying that the FP4 has VoLTE but not VoLTE roaming: VoLTE Roaming (4G calling abroad) No; VoLTE (4G calling in UK) Yes.
In another post, someone linked to a website with this question:
Does Salt Mobile APN support VoLTE?
Yes, but support depends on your phone’s IMEI being whitelisted on Salt Mobile APN’s IMS core. If your VoLTE toggle is greyed out, it’s likely your phone is not in Salt’s VoLTE database, or your APN configuration is missing type: ims. Official support is best with newer Samsung, Apple, and OnePlus devices.
I will try to contact my provider to know if Fairphone 4 are in the database or not.