This question is an exact duplicate of:
Is my aufenhaltstitel still valid if my husband changed his employer and switched to EU blucard. Although my husbands previous employer didnt de register him and didnt cancel his aufenhaltstitel as well. And also even if I have not been de registered from germany but my address is showing unknown. What does that mean? Is my aufenhaltstitel still valid? Have I been de registered or is it that they are unable to find my address and hence showing unknown? I have been away from germany for more than a year but the consulate in my home country say my visa is valid. But now I got to know this? What does that mean?