Sudden night accidents

So, our daughter has been potty trained for over an year as of today. It was relatively easy to train her and soon we assumed we she was accident free. However, it has been over two weeks she is bed wetting every single night. When I ask her why did not she get up to pee, she says she called us but we did not hear. That is not possible because yesterday we checked on her at around 11:30 pm, she was already wet, she has not called anybody and she was deep asleep. Any ideas why can it be happening? We did change an apartment and one can assume its a moving related stress but it happened a month and half ago, she did fine until two weeks ago. Ideas?