IGN France (broken)

I have the latest version of Locus Map (4.15.2) on Android with an IGN subscription.
For several days (it's complicated in the field) I can't see IGN maps anymore: I have the error "Unknown problem". I tried to download maps and same thing: it doesn't work.
As I pay a subscription for access to these maps and the problem is recurrent I would like to be able to use the service normally.

EDIT : I'm sorry. I see that there is already an answer to this problem (I had missed it and I have indeed an old phone). I will try the beta version.

https://help.locusmap.eu/topic/31394-cartes-ign-inaccessibles