GlockApps property

https://glockapps.com/spam-testing

It will check the reputation of your sending IP, your authentication, and real email placement across different mailbox providers and show you a picture of what is really going on and what you look like to email receivers.

The information it will gather will help you determine different things that can potentially lead to poor deliverability: some of them are content related, some of them are IP related, some of them are reputation related. Plus, you'll get suggestions you can follow to make sure that your future email campaigns are getting to the Inbox and to send better messages that people will convert on.