"Sender address rejected: not logged in" when sending from remote server with a inactive local domain

I set up a new email domain for a soon to be client example.com who is currently hosted by current-provider.nl. I set the domain as inactive. Added the mailbox user@example.com with default settings. When client tried to sent me a email, it was rejected, see log:
Oct 30 13:32:59 pascal postfix/smtpd[28002]: connect from main.current-provider.nl[12.34.56.78]
Oct 30 13:32:59 pascal postfix/smtpd[28002]: NOQUEUE: filter: RCPT from main.current-provider.nl[12.34.56.78]: <user@example.com>: Sender address triggers FILTER lmtp:[127.0.0.1]:10026; from=<user@example.com> to=<postmaster@mycompany.net> proto=ESMTP helo=<main.current-provider.nl>
Oct 30 13:32:59 pascal postfix/smtpd[28002]: NOQUEUE: reject: RCPT from main.current-provider.nl[12.34.56.78]: 553 5.7.1 <user@example.com>: Sender address rejected: not logged in; from=<user@example.com> to=<postmaster@mycompany.net> proto=ESMTP helo=<main.current-provider.nl>
Oct 30 13:32:59 pascal postfix/smtpd[28002]: disconnect from main.current-provider.nl[12.34.56.78] ehlo=2 starttls=1 mail=1 rcpt=0/1 quit=1 commands=5/6

I tried disabling "Enable receiving", but that didn't fix it. After removing the domain from my setup, I could receive email from user@example.com.