When mailboxes from some particular domains are substituted to "Email Adrress" of Contact form from Web Presence Builder, such emails are not delivered.
Enable DMARC to check incoming mail option is enabled at Plesk > Tools & Settings > Mail Server Settings
DMARC policy of such domains is reject:
# dig +short txt _dmarc.example.com
"v=DMARC1; p=reject; pct=100; rua=mailto:firstname.lastname@example.org;"
The following lines can be found in
CONFIG_TEXT: server dk_check: Starting the dk_check filter...
server dk_check: DKIM verify result: DKIM Feed: No signature
server dmarc: Starting the dmarc filter...
server dmarc: SPF record was not found in Authentication-Results:
server dmarc: DMARC: REJECT message for email@example.com
server postfix-local: message discarded by a mail handler
Emails are rejected by DMARC check handler.
The behaviour is also confirmed as Web Presence Builder bug with PPB-4579
Use one of the following workarounds:
Disable Enable DMARC to check incoming mail option at Plesk > Tools & Settings > Mail Server Settings
Specify E-Mail as "Text" field in WPB contact form: