Identifier required but not working

Hello,

I'm unable to update my email box. I'm being asked for my credentials, which I provide, but then there's a synchronization issue with my account. I contacted the La Poste.net customer service yesterday but have yet to receive a response from them. I've searched for a solution online but couldn't find anything that suited my needs. I'm reaching out to you in hopes that you can assist me, as this is becoming quite bothersome.

Best regards