Why isnt my phone connecting to my wifi?

[AC Question]

I have a very old pantech phone that I have just recently tried using again after months. Every time I try to connect to wifi it says connecting then says disconnected. I have tried factory reset, the airplane mode thing, restarting the phone, and router. I've even tried manually putting the information in. This is all I have for a phone. I can't afford a new one or to go get it fixed. What do I do?