An update has been released about the damaged radar station that caused SpaceX to have to delay the next Dragon flight again — there was an electrical short at the TEL-4 tracking station at Kennedy Space Center (operated by the USAF, which leases the site from NASA), and repairing the damage is expected to take at least three weeks. The USAF is exploring the possibility of reactivating another site, but at present it appears the next Eastern Range launch will be the Atlas V originally scheduled for March 25, and it will probably fly in mid-April. Dragon will be next in line after that.
The reason all Eastern Range flights are on hold is because the radar network is crucial for relaying the destruct command if a rocket goes off course. The USAF and NASA have begun testing a GPS-based alternative system, but it’s not ready for use yet, and neither Atlas V nor Falcon 9 are equipped for it.