I checked in our system and I saw that your email was in a suppression list. Atlassian attempted to send an email to your email address a few weeks ago and received a hard bounce response from your mail server, which indicates permanent failure. The email is then placed in a suppression list, as we no longer try to send to non-existing emails.
I went ahead and removed your email from the suppression list. In case any Bitbucket invitations were sent to that email, please ask one of your admins to resend it now, as the previous ones were dropped.
Please feel free to let me know if things are ok now and if you need anything further.