BMS API | Error 500 when calling get attachments from invoice

Question

I get an error 500 when I am trying to get attachments from invoices.

API call used is:  

GET https://server_name/api/system/attachments/{moduleId}/{objectId} 

Answer

 An invoice with no pdf generated will give you these issues. 

Regenerate the invoice to recreate the PDF. 

 Please contact Kaseya Support if you continue to receive this error.