[SOLVED] Whitelisting / relaying for local subnet

Oct 1, 2019
Hi all,
why does Mail Proxy Whitelisting has no effect on the HELO Syntax check?

Dec 18 10:15:20 mx11 postfix/postscreen[11818]: WHITELISTED []:54051
Dec 18 10:15:20 mx11 postfix/smtpd[11807]: connect from **********l[]
Dec 18 10:15:20 mx11 postfix/smtpd[11807]: NOQUEUE: reject: RCPT from **********[]: 504 5.5.2 <*******>: Helo command rejected: need fully-qualified hostname; from=<backup@********> to=<support@********> proto=ESMTP helo=<*******>

and furthermore, if I disable HELO checks, I am getting a "relaying denied, despite the Host is in the same subnet as the Mail Gateway:

 Dec 18 10:24:31 mx11 postfix/postscreen[12572]: WHITELISTED []:54076
Dec 18 10:24:31 mx11 postfix/smtpd[12587]: connect from *********l[]
Dec 18 10:24:31 mx11 postfix/smtpd[12587]: 50CA8405BD: client=**********[]
Dec 18 10:24:31 mx11 postfix/smtpd[12587]: 50CA8405BD: reject: RCPT from ********[]: 554 5.7.1 <support@********>: Relay access denied; from=<backup@*********> to=<support@*********> proto=ESMTP helo=<*********>

According to Documentation relaying is allowed in local subnets:

Can someone explain?
Thank you.

edit: Even if I add the local subnets under "Networks" I get a "Relay access denied"
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