Exception (400): List has no rows for assignment to SObject when saving OmniStudio Document Template

Hi all, 

I am using the OmniStudio Document Template Designer to update a current packing slip. I replaced a line in the actual text of the document, so nothing essential to the functionality. I made a new version of it and then replaced the file with my edited version. When I try to do that, it throws this error:  

I've been trying to troubleshoot this for a bit and cannot seem to figure out the problem. Would anyone know how I can troubleshoot more or potentially fix this? 

Thank you!