I have an ArcGIS Server service where I have a related inspection table with attachments enabled. The Attachment Viewer does not support this? The attachments have to be related to a feature class, not the related table?
Thanks for reaching out about this. Attachment Viewer can support viewing attachments in a related table, but the table needs to be related to a Feature layer that also has attachments enabled. This should also be supported with ArcGIS Server services. What version of ArcGIS Enterprise are you using?