Question Can't connect to a wifi even if my password is right.

Aug 10, 2019
The building beside us has strong wifi and it is free until they decided to protect it with a password. And then, since our neighbor knew the password, they gave it to us. For the first few weeks, we were connected on the building's wifi. Until one day, the wifi's strength has weaken. I can still connect but the wifi signal is very weak. So I tried to forget the network, hoping it would solve my problem but then, when I entered the password, it said that my password was incorrect. But it said that the password is unchanged so I'm 100% sure that I typed my password right. I tried it with my mom's phone and did the same thing. I forgot the network and entered the password but still, it won't connect. My sister's phone can still connect though. I tried to connect it to other wifi and it worked pretty well. Only the building's wifi is what I'm having problems with. I don't know how to fix this and what's the reason for this. Are our phones blacklisted? Is it because of the weak signal?

Any help will be deeply appreciated. Thank you very much!