Cannot sign in with username and password

I am unable to sign in to my account using my username and password. GitLab is giving me this error message:

invalid login or password

I tried resetting my password, and I was able to do that, but I still cannot sign in.

I tried re-confirming my account, and again, I was able to complete that process but I am still unable to sign in.

I tried pushing code to my private repo to see if git would give me a more detailed error message, but I was able to push code to the repo.

Finally, I used the BitBucket SSO option, which requested permission from BitBucket even though I had already used it in the past and imported a repo from there. That brought me to the MFA screen where I was able to complete my sign in and access my account.

Why am I not able to sign in with my username and password? Why didn’t the error message state that I needed to use a single sign on service (SSO)?