[Self-hosted] Admin portal "...page is not found."

My self-hosted BW installation is working and I was able to successfully send & receive the verification email (so I think my SMTP setup is correct). Then, following the instructions on [1] I added my email address to the ’adminSettings__admins= ’ line in: ./bwdata/env/global.override.env.
I then rebuilt and restarted my BW installation, and updated the database.

However, when I try to access my admin portal at https://mydomain/admin, the page only displays a single line that says: “Sorry, the page you are looking for is not found.” with a “Back” button below it.

Any ideas as to what I might be doing wrong? Thanks in advance for any suggestions.

[1] https://help.bitwarden.com/article/admin-portal/