Same issue here -- trying to cancel (for credit, not refund) JFK-MEL RT beginning 4/6 and getting $400 "cancellation fee" shown even though this should have a waiver per the DL coronavirus policy. Holding off on the final click for now -- may try to call DL after the Europe rush abates (and/or in the middle of the night). No status on DL so on the regular #.
(Policy from Delta website applicable to this: You may choose to cancel your trip, and use the value towards a future flight. You may cancel your flight and apply any unused value of the ticket toward the purchase of a new ticket for a period of one year from the original issue date. The change fee will be waived, however fare difference will apply for new travel dates and will be collected at the time of booking the new ticket. To cancel your flight, visit My Trips on delta.com and click on "Modify Flight" then choose "Start Flight Cancelation".
This is as opposed to the option above, which is "Change to a different flight.")