I feel your pain. I have had similar problems over the last 15 years that I have been running my own mail server, but mostly with hotmail when they were the gmail of their time. (they would accept the mail and then silently drop it)
I would maybe change the SPF record to fail instead of soft-fail (~all to -all).
I have a @gmail.com account that I use for testing whenever I change something.
I would maybe change the SPF record to fail instead of soft-fail (~all to -all).
I have a @gmail.com account that I use for testing whenever I change something.