I am using Docusign for Esignature Salesforce Managed package. Enabled send as System user option with a docusign admin user. but when I am trying to send the record for signature through apex I am facing below error "A Mergefield value for a tab could not be retrieved. Unable to connect to the service. Failed to connect to the salesforce service"
When i try to send the document as a docusign user, the record is sending succesfully.
Tried logging out and connecting the account. Tried deleting the app at docusign and connected again. checked whether user has access to the fields. User has access to all the merge fields.