Reply messages duplicating about every hour

[Jason V.]

I am experiencing an issue where reply messages are duplicating almost each hour. I see the same reply message within the message string. I received the reply message, however it keeps trying to resend constantly. I checked Cloudmailin and am seeing the following response for each of the messages: 500
This is how your HTTP server responded (or the error we encountered with it)

Any ideas on what might be going on? Thanks in advance for your help.

[Anonymous]

Hi @jasonvphase2solutions, Sorry for inconvenience

Please let me know your site url

Regards