I just got my Fairphone (from the second batch) and i am quite happy with it, except that i cannot open the mms.
And I do get some of them frequently and need to see them (professionally speaking).
FP running in France with B&U (Bouygues) as provider.
Many thanks already for those willing to help.
Did you check the APNs (Settings > Wireless & Networks > More… > Mobile Networks > APNs)? In my configuration there are two APNs, one for normal mobile data connection and one for MMS.
Maybe the following page helps you out: https://assistance.b-and-you.fr/questions/225438-veux-parametrer-smartphone-android-pouvoir-utiliser-services-sms-mms-internet-faire . Usually you can request a message from your provider to your phone which includes all the necessary configurations for data connection and MMS.
Many Thanks to You, @Stefan,
Your first hint did it : it was the APNs.
I am really glad to have this trouble solved in the day with your help ! God bless You !