PeerTube service at watch.ocaml.org is unable to email Gmail accounts

[mtelvers]

Despite our earlier attempts to resolve this by providing a reverse DNS entry for watch.ocaml.org, Google still rejects emails from our IP address. The reason given in the error report is

The IP you're using to send mail is not authorized to send email directly to our servers. Please use the SMTP relay at your service provider instead.

This may be due to the SPF record on ocaml.org. We could try adding ip4:163.172.166.101 ip6:2001:bc8:47e4:202::1 to the SPF record.

However, may I propose we work around this using Gandi's SMTP relay rather than direct SMTP delivery?

I have a test domain at Gandi, and have prototyped this solution by creating the email address [email protected] and configuring PeerTube to that account for authenticated SMTP sending via mail.gandi.net. This works sending to my test Gmail account.

Is there an existing [email protected] account which could be used for this, or could one be created?