@joluinfante 

Hi

I had same problem.

If you have another phone then download app and try on different phone.

If not try deleting the APP and downloading again. Although no APP update was showing its different as slightly different look with new one.

Once done on new phone/app i was then asked to put in new password rather than asking for old one.

  @joluinfante 

When new APP opened it says open updated new version of APP

Yes, I saw that message. He sent me to the google repository, and it did nothing. That message is like a liar. From there, something started to go wrong with the nc450. I understand that this is an old line, but, well, in Argentina, replacing all the cameras with tapo is expensive, and if you don't you have to manage 2 applications (the tpcamera for the old line and the new application for the tapo, a problem ). On the other hand, the old line does not have support in home assistant. And tapo, I have no idea if it has support or not... Yes, I have verified that tapo does not have direct viewing in Google Home. That is to say, it is a problem for the inhabitants of third world countries, where technology arrives late and expensive.

  @joluinfante Hi, the Tapo app is unable to manage the NC450, so if you have both cameras, you can use the Tapo app to manage the Tapo camera and use the tpCamera app to manage the NC450. By the way, are you talking about the password for the TP-Link account or the password to log in to the NC450? They are different passwords and maybe a screenshot of the login page can clarify the situation you encountered.

  @Summer_S Hello. Thanks for the reply. Finally, I discovered that the problem is that that camera (which I use with tpcamera, like the rest of my cameras), does not work well on the local network (the others work correctly, and are even older). Since I usually don't check my cameras when I'm home, I didn't understand what was happening. When I connected via internet, things worked. I understand that this must have to do with some type of confusion in the mesh network (which I have working with tplink devices as well). Curiously, I think the problem appeared after tpcamera told me "there is a new version on the internet" (which was not the case, because it did not update anything). But, well, for the moment (now that I understood the situation), I'm not worried. I am satisfied that it is working from the internet, which is what I need. I can't remember if this failed before. Surely, in time, the old cameras will start to fail, and I will have to migrate to tapo.

  @joluinfante voce encontrou a solução para o seu problema?,estou com duas NC450 semi novas ambas com o mesmo problema,não faz a formatação de fabrica,já tentei de todas as maneiras.