The following plugins, technologies, and themes are know to be incompatible with Postmatic. Workarounds and alternatives are offered when available. See details below.
If you are running this plugin be sure to not enable caching of the Postmatic widget. Just like this:
Certain Lazy Load Plugins
Some lazy load plugins cause trouble with our email template. The good news is that there are plenty that work well. You can view a list here.
This plugin can block notifications of inbound email.
This plugin can disable mailing if Postmatic is included in selective plugin loading.