I tried looking around for a solution since i am bored and found you with this issue and this is what i found and the info can be wrong.
Unfortunately, EA's services are not officially supported in Iran due to international sanctions. This means even with workarounds, stability and access can't be guaranteed. Ultimate Team, especially, depends on real-time online services that can be geo-blocked.
I may have the wrong information but unless this is confirmed by an EA-employee or similar, I do believe my source to be correct. Until you have an official answer you are sadly stuck with only offline modes but Career Mode being an issue is weird since from what i know it is as offline mode unless you have to download the latest data or something like that.