I had finished installing RabbitMQ (my first time dealing with it) on a CentOS 7 installation and was trying to log into the web management console but to no avail.
I had created an admin user and set administrator tags for the user since it seemed that it was highly discouraged to use the guest user for logging into the web management console remotely.
I knew the credentials were correct but the login page kept telling me "Login Failed" while the logs showed:
2020-02-19 09:56:27.069 [warning] <0.622.0> HTTP access denied: user 'rbt_admn' - invalid credentials
Googling only seemed to give results for people facing similar problems but who were mostly trying to login with guest or had incompatibility issues but I was sure none of those were the problem for me.
After a sleepless night of troubleshooting, I was able to solve it. So I'll post my solution below in case this is of use to someone in the future.