can’t remove roaming letter above signal bars

I’ve researched a lot and I can’t find any solutions to this problem. A couple of months ago I traveled by plane, and when I arrived and turned off airplane mode (I have it always turned on) I had this r above the signal bars. I think it’s because I got outside my isp area when I was on the air, but now I’m back in my city and I can’t get rid of it. I’ve trying manually selecting the isp, turning on and off the roaming and the mobile data in the configurations but nothing seems to work. What else could I try?