Migrated to new server but mails still going to old server

I migrated one domain (There is several domains) from old server to new one, let’s say server5.com. I used VM documentation.
I disabled this domain on old server. I changed DNS A records at hosting
Now all ok, but if I send messages from other domain on old server, mail going to old server even if I already disabled it.
Where I need to change configuration on old server to clear cache or DNS records or something else please.
I really need help. I stucked with migrating.

Hi, mail is using MX records, not A, that is the problem. if you only use A records to point to hosting you have to update the MX records, or better use name servers to avoid such problems. Best would be before you migrate to change the refresh to 300 [ means 5 minutes] instead of the 14400 which seems to be standard.

Thank you RavenKing for reply.
let say domain is server1.com and IP
So I have this records on hosting:
server1.com. 300 A
www.server1.com. 300 CNAME server1.com.
server1.com. 600 MX 10 server1.com.

So I Just changed IP in A record.
Both servers old and new are in local network, but using different outside IP’s.
What else I can do??
Thanks in advance!

If you go to virtualmin>server configuiration>suggested dns records are they the same as what you have inputted manually?

If you use the suggested records in virtualmin above at your SOA you really cant go wrong.

for example mine has the following relating to mail:

mail.domain.com A 3600 (where “mail” is the mail servers public name)

domain.com MX mail.domain.com 3600 10

as well as txt records for SPF and _DMARC