sql – Database is in read only mode

I have database in Azure. To this DB is connected app services wit soem API. API (.net) is not using tables, but is calling sstored procedures. And one procedure (whichj is updating data) throwing exeption that data base is readonly mode. What can be a reason of that. There is only one isntance so there is not a problem with connection to read only instace. DB is not in read only mode – othere procedures woorki as well.

I check if DB is not in read-only, mode. I check if there is a problem only with some table or with all – any update is causing the same problem.