Are you on- premise setup or it is hosted by Adobe.
As per the error in screenshot, it seems that the delivery is failing due to the missing Md5Digest installed on your Postgres database.
Usually occurs when extension "pgcrypto" not installed. This Extension have to be created once per database. And the pgcrypto extension is special as it can only be created by the database superuser (normally postgres).
If you are on on premise setup , I would suggest you to please ask DBA at your end to further look into this concern/Error.