A reader reported being able to connect to hotspot with Simple Mobile but not being able to connect to the Internet. Also something about getting a T-Mobile log in screen. That part wasn’t clear to me.

I don’t know what the specific problem you are having is.

You did not say what type of phone you have and I’m not clear if only your roommate isn’t able to use hotspot or all the members of your family plan.

I’d start by restarting your phone,
Check to see that the APN is set correctly, https://www.simplemobile.com/apn
I’d also try enabling Wi-Fi calling , https://e911-reg.tracfone.com/

If none of that works, and hotspot works with one of the phones on the plan, I’d try swapping SIMs to see if the problem seems to be with the SIM, the phone, or both.