Using NextDNS with another profile

Hi, when I'm logged into NextDNS, it shows "This device is using NextDNS with another profile."  This other profile must be the one I first set up with NextDNS, but I'm unable to log into it - and having set up a new profile, I guess directing it to the same endpoints just used the old profile? Help! Any 'forgotten password' for the email address I used didn't send an email, so I'm really in the dark here about what to do next... help appreciated.