I didn’t need all that just what I pasted, section above that but I can see spf=none so you need to fix it. Use mxtools to test and there is plenty of info on the internet on how add these setting and on the forum this has been discussed. These are basic things to know if your running a mail server.
ie Add your SPF record at your domain provider - Google Workspace Admin Help
@paulfromsurry - A little bit of advice always redact/edit any posting on the internet to remove ALL references to IP addresses, domain names and emails as you are inviting bad elements out there who scan the web for such things to obtain targets for malware. Although I would guess the security of this site to be pretty good, there may still be bots or idle users who may still gain access and scan the site for such information, it is not worth the risk. A clean IP address is like gold - protect it.
You need to copy the TXT record for DKIM from your Virtualmin to Cloudflare DNS. Go to DNS records on your Virtualmin and click “Manually Edit Records” button at the bottom.
DKIM is a TXT record. You need to look for YearMonth._domainkey.example.com. Copy it entirely to Cloudflare it’s a long record.
Basically, you need to learn to set up a mail server properly
A useful way to test one’s mail is try a test at https://www.mail-tester.com/ . What score does your email get? (Note that they give a few free tests each day)