Maybe it's because the rtp record setting is not working well due to AWS reverse DNS application.

Currently, spam has been determined when sending emails.

I'm looking into it
I am using AWS and I have to apply for the lifting of the restriction on Elastic IP, so
I sent the application by referring to the following URL.

http://toatoshi.hatenablog.com/entry/2013/07/04/091846

I submitted my current ElasticIP and the domain hoge.example.com (provisional) that I set as A record.

However, I received the following response:

The mapping for this reverse DNS entry is failing because the PTR record does not match the record for that domain. We currently require the forward record to match the PTR record for all reverse DNS entries.

You can provide us with an alternate hostname, or configure the Record for this domain to match the desired PTR record on your side.

I would like to re-submit the necessary information after attaching it while researching my knowledge of PTR records.
I don't know what to offer to pass the application.

I would appreciate it if you could tell me how to deal with this situation.

Thank you for your cooperation.

We have added ptr records to Route 53 by referring to the current situation.
https://forums.aws.amazon.com/thread.jspa?threadID=115473

$nslookup-type=ptr [IP address]

has not changed much at this time.