Issue for delivering Gmail with second domain

1

Hello all,
i have set up a second domain and when i try to send an email to gmail from the second domain i got this error:

Undelivered Mail Returned to Sender

host gmail-smtp-in.l.google.com[ww.xx.yyy.zz] said:
550-5.7.26 This mail has been blocked because the sender is
unauthenticated. 550-5.7.26 Gmail requires all senders to authenticate with
either SPF or DKIM. 550-5.7.26 550-5.7.26 Authentication results:
550-5.7.26 DKIM = did not pass 550-5.7.26 SPF [second.domain] with ip:
[ww.xx.yyy.zz] = did not pass 550-5.7.26 550-5.7.26 To mitigate this
issue, please visit Gmail’s authentication guide 550-5.7.26 for
instructions on setting up authentication: 550 5.7.26
i can deliver to some other email adresses but fail with Gmail.
please can you help me figure out.
Thanks in advance

2

Did you force ssl cert for that domain and potentially wait like 24 hours for dns propagation to work?

3

Are you using external DNS or using the MiaB server to handle DNS?

4

i am using MiaB server to handle DNS ; i have set ns1 and ns2 to point to mail.domain1.com from the domain2.com DNS page