Cannot connect to wifi: no IP address

I have the same problem.

Today I had to reset my router due to an internet problem and now I cannot connect to wifi. Usually on a PC it’s as easy as just typing the password in again but it won’t seem to let me do the same on Mac and I have no idea what I can do.

I have looked in the TCP/IP tab but no IP information is displayed anywhere- it’s just blank…

Any help is greatly appreciated