Anecdotal information: I run my own mail server and manage a number of small business clients who have mail servers. Email trust is getting more and more tedi

Anecdotal information: I run my own mail server and manage a number of small business clients who have mail servers. Email trust is getting more and more tedious. Recently I was resolving a domain registrar issue with Network Solutions. They required forms filled out and signed, a copy of a utility bill from my client, a copy of my ID... I bundled up everything and emailed them the scans. I contacted them 5 business days later, they claim to never have received it. I sent it again while I had a rep on the phone, it went into their spam hole, probably due to size of attachment. They helpfully suggested I get a GMail account to send the same message. They are my registrar, they host my DNS, including my MX record. I have an spf record... I thought it was pretty farcical, and a sad statement of digital trust/authenticity. Some of my clients are giving up and just going with the flow, I have had several conversions to Google/Microsoft cloud-hosted solutions for email...