550 5.0.350 Remote server returned an error -> 550 Delivery not allowed to <sendmymail.nl>

Hi,

As you see above, my emails are not going to the internal users, They are able to send, but ot able to receive.
In the SMTP Receiving log it shows up like: Reject relay to …

Anybody able to help me?

This is what I get from MXToolbox:

Connecting to 213.125.112.50

220 sendmymail.nl [735 ms]
EHLO keepersomething
250-PC-Monique Axigen ESMTP hello
250-PIPELINING
250-AUTH PLAIN LOGIN CRAM-MD5 DIGEST-MD5 GSSAPI
250-AUTH=PLAIN LOGIN CRAM-MD5 DIGEST-MD5 GSSAPI
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250-SIZE 10485760
250-STARTTLS
250-HELP
250 SPF check for <keeper-us-east-1c.mxtoolbox> returned no results [779 ms]
MAIL FROM:
250 Sender accepted [1242 ms]
RCPT TO:
550 Relay denied for [726 ms]

LookupServer 4660ms

I suspect it is this setting:
image

When I disable Require Authentication, the user is able to receive, and NOT able to send.
If I disable this, the the user is able to send and is NOT able to receive.

I’m stuck.

Cheers, Frank

PS, I had to remove some .com’s from the text (2 links per post policy).

Hello Frank,

The usual situation is to allow Local Delivery without authentication and Remote delivery with authentication.

Thus my advice is to disable “require authentication” option from the referred setup and continue with your second problem: user could not send messages.

For this second problem - please confirm that your users are trying to send via an authenticated session.

Please advice.

BR,
Ioan