MFD
Common Errors: xxx Not Communicating
If the MFD is giving just one error, troubleshoot the MFD via the Troubleshooting Guide 600-00718-000 Rev00

http://dealers.avidyne.com/files/downloads/600-00718-000-R0-EX5000-TG.pdf 

If the MFD is giving multiple errors (pictured); check the date and time of the MFD (System Time)
- is it set to Auto, Manual?
- If Auto, check your GPS source to ensure it is getting a good signal
- If Manual, check the UDT time and set accordingly

Make sure the plane is outside and can get a good GPS Signal, confirm the error have been resolved.