Postfix, why can't send mail by script?

Question

FreeBSD

Good evening.
A bunch of Postfix + Dovecot + Spamassassin was installed on Freebsd according to the article:
https://habr.com/ru/post/476148/

Everything started up with minor adjustments. Installed Roundcube.
It enters the boxes, letters leave and come.
But letters stopped leaving php scripts, in the logs it says that relay is prohibited.

Registered mynetworks
= 127.0.0.0/8

Added to the rules:
# Rules for sending mail
smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated reject_sender_login_mismatch, reject_unauthenticated_sender_login_mismatch, reject_non_fqdn_sender, reject_unknown_sender_domain

# Rules for receiving mail
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_multi_recipient_bounce, reject_unknown_client_hostname, reject_unauth_destination

After that, the php mail function worked.
But now the following error is in the logs:
Dec 14 17:29:15 myserver dovecot[79530]: auth-worker(6962): sql([email protected]): unknown user
Dec 14 17:29:15 myserver postfix/pipe[ 7069]: B0E293EC45: to=, relay=spamassassin, delay=1.9, delays=1.7/0.01/0/0.26, dsn=5.1.1, status=bounced (user unknown)

Why is there some sort of external mailbox check for existence? Where to dig here?