T-Mobile home Internet app

I cannot access my Tmobile internet app because it no longer recognizes my password. My smart TV lists my Tmobile wi-fi, but will not accept the password, either. Other devices are on the same wi-fi connection, including another TV.  What can I do without disconnecting everything?  The problem TV is a Samsung, and has always been connected to this wi-fi network and worked fine, until this week. I can successfully connect the Samsung to another provider that is also in my house but prefer to keep all my devices on the same Tmobile internet.