Impossible to remove account (It's not showing up in account list under 'accounts', but it does fetch mail from it)

But when retrieving e-mail, it DOES fetch e-mails for the mentioned account.
And also, when sending a new mail, it shows up in the list of from addresses. Notably, it doesn’t have a name set to it, which might be the reason it’s not showing in the account list settings:

Question is, how do I remove an account that’s not in the account list UI?

EDIT: this is for a client who uses the pro version of EMClient.

If the account is not setup in eM Client, then the application is not connecting to that server to get the messages. Maybe the user has the account forwarded to one they have setup in eM Client.

It IS setup in EMCLIENT in the past.

It’s just not showing in the settings UI anymore.

Furthermore, it can be selected as “FROM” address and can actually send mail under that address, as mentioned in the first post.