Ferber Method help

My daughter is 1 year and 3 months and we started the Ferber method about two weeks ago. The first week and a half was great. She would finally sleep through the night without waking up to cry. Now after about two weeks she is waking at night again. She doesn’t take long to fall asleep. It takes her anywhere from 2-4 minutes but she has started waking to cry again. She usually soothes herself back to bed pretty quick. But is this normal?