table doesnt exist erroe

I have installed the Eternal Database Authentication Reloaded plugin onto my WordPress site. I wanted WordPress to authenticate using a database of existing users. however when I try to get to the site, I am confronted with an error that says: Table “testdb.mailbox” doesn’t exist. I have rechecked the settings and as far as I can tell they are all correct. I’m not even sure why it would be looking at testdb. (this was an non production db for WordPress) Under settings-External db settings, I have filled in the fields as follows:

Database type: MySQL
Host: localhost
name: vmail (name of external database)

I did not include the user name and pass on this forum but user does have privileges on this database

I am able to deactivate the plugin in order to run normally, but I would much prefer to use this other database as I am trying to create a single registration point

https://ww.wp.xz.cn/plugins/external-db-auth-reloaded/