What is the Administrator password? I don't recall ever setting one. I live alone; sole user of this computer. I chose to bypass the password when logging on.

Did you already try the general troubleshooting mentioned in this article?

If you forgot your Mac login password

If this does not work, follow this one:

If you can't reset your Mac login password

Reset Computer Password  for the Administrator Account Password

Intel Computer

1 - Restart computer and immediately hold Command + r keys

2 - Top Tool Bar >> Utilities >> Terminal

3 - Type resetpassword as one word and no spaces

4 - Press Return key

5 - Follow the prompts and remember the New Password

Apple Silicon M1 Computer 

1 - Choose Apple menu > > Shut Down.

2 - Press and hold the power button on your Mac until you see “Loading startup options.”

3 - Click Options, then click Continue. 

4 - Top Tool Bar >> Utilities >> Terminal

5 - Type resetpassword as one word and no spaces

6 - Press Return key

7 - Follow the prompts and remember the New Password