How to retreive a lost username?

I have 4 accounts in my Homey, 3 of them i know the logins but the 4th i do not, i lost it.

I have no idea which email adress (username) I used, in Homey settings only names are displayed, not usernames/email adresses.

Is there anyway to see which usernames (email adresses) have access or are linked to my Homey?