The requested vessel with name ANTON CHEKHOV and MMSI:0 and IMO:6806121 is temporary not in our database.
Perhaps you mean one of the following ships:

Vessel name IMO MMSI In range Destination Last report
ANTON CHEKHOV N/A 273335180 Oct 02, 2017 09:55 UTC

Also, you may try to find the vessel in our comprehensive Vessels Database or track this ship on the map.