If the 'send' button is grayed out, we advise that you check the individual placements.  Lines with valid errors will have a red box containing the number of errors on the LEFT side of the placement; those are validation errors. 

Check for fields that are highlighted blue, those fields have been marked as required by the agency and must have a value entered. 

Fields with red lettering are also indication of an issue, hover over the field for more details on the error. 

Once all validation errors are removed the send button will appear again and users will be able to send revisions back to the agency.