Google putting all mail to spam

This question is related to some software for schools and one part is for the schools to send information to students and parents. But all mail end up in Gmail spam folders. If i look at the google postmaster tools for the last 120 days it says this:

• User reported spam: 0%
• Ip Reputation: 100%, but only for one day. No other records
• Domain reputation: High (on top) but with one day falling down to medium (when the schools starts after holiday)
• Spam feedback loop: 0%
• Authenticated traffic: 100% (DKIM success rate, SPF success rate, DMARC success rate)
• Encrypted traffic: 0% (inbound tls rate)
• Delivery errors: 0%

Allmost like they just put it to spam because its a competitor to their own products.

(by some strange reason, when the school where my kids go to send a messages, they arrive at my private gmail inbox, but not for other parents)

Is it time to give up on using email and force the receivers to install an app?

I dont know what more to do to prevent the mail from going to spam. Any advice on what to do?

Theoretical question: Does google not like it when the user never visited the page (same domain name as used for the sender email address) and yet receives emails from it? (email etc is collected from schools and registered by them)

These technical requirements are met:

• SPF setup
• DMARC setup
• DKIM setup
• IP Reverse lookup to sender domain

It is only google sending the mails to spam

Because it has been abused so persistently by bad actors, if you want to send newsletters these days, you must offer a method of unsubscribing to the recipient (preferably including RFC8058), whether unsubscribing has undesirable real-life implications or not.

When an organization has an operational requirement to be able to reliably send information to people, they need to fight about this outside the premises of mail providers. The mailbox provider must not become the final arbitrator on whether someone was supposed to accept a mail or not, they are neither willing not equipped to do this.

All they can do is ensure that the mailbox owner retains control over his Inbox, and if this is not ensured by the sender, they can and will ensure this with actions affecting all mailings of the sender.

Two suggestions:

1. Provide a link (possibly including or accompanied by credentials) in the very first opt-in request/confirmation mail sent per account.

   • Ensure that everything received via mail could also be accessed through that link.
   • tell people not wishing to subscribe to your newsletter to bookmark that link
   • have a procedure documented for the senders on how to send that link again to single recipients having lost it
   • Give senders easy access to check which recipients have opted in and which need to be notified through other means.

2. Limit the Unsolicited mail by more strictly enforcing separation between

   • "sent because some helicopter parents want to know it"
   • "recipients need to know and have no other method of knowing about" and
   • "recipients need to specifically confirm having received".

   Google will helpfully treat different email campaigns differently if only you make it easy to tell them apart.

Link to Google relevant documentation, which I recommend to read more as list of "minimum requirements" than "suggestions of what else you could do".