Exchange Server 2016 On Prim and Dynamic IP and (5 Domains)

We by Email Store/Forward and SMTP Outbound Relay for all the domains and we use only the creational for one of them for example Domain1.

the issues now when the user send an email for example 7 company's only 2 they are receiving and the rest no.

SPF , DIKM and DMARC should be one for all the 5 Domains or no.

we open so many tickets with DYNU but no answer.