Emoji :thinking: Problem
Part of the SFTP Credential configuration is to assign the Inbound E-document Web Service Role (Docs Full) to the Integration user that holds the authentication keys. Role permissions checking is necessary, especially when pre-requisites are not followed before bundle installation. Ignoring this step may lead to the abovementioned conversion error and resulted to the absence of the following permissions:
E-document Audit Trail
E-document Sending Methods
Emoji :seedling: Solution
To check roles permissions:
Navigate to Setup > User/Roles > Manage Roles.
Select and edit Inbound E-document Web Service Role (Docs Full).
Under Permissions > Custom Record add the permissions if missing from the list.
Save the role.
During implementation, it is important to check this step regardless of whether the pre-requisites were followed or not.
Emoji :paperclip: Related articles
Role Permissions - Staria FlowAP SuiteApp - Confluence (atlassian.net)