I fixed the problem myself just by using Scotch tape. I didn't really tape the connector to the port to keep it in place, but I put 3 small layers of Scotch tape on top of the connector. Then I inserted the connector. It's not really easy to insert the connector because it got thicker, but that's the reason why it works: the thickness of the connector with the Scotch tape "simulates" the pressure of the locking tab.
'''TL;DR''': put small pieces of tape on top of connector, then insert connector. Test front camera and add layer of tape if necessary until you reach suffising pressure.
Excuse me for my English and good luck to anyone with the same problem :) feel free to contact me if something isn't clear.