If you are using NextPVR v5 or later, the instructions for setting up an HDHomeRun will be different.
Note: you must have a subscription to Schedules Direct in order to use their EPG data. This is required for any EPG data for HDHomeRun PRIME, and recommended for ATSC/clear QAM.
Check your firewall configuration and make sure that the NextPVR, NRecord, and NDigitalHost programs have full network access.
For HDHomeRun Connect/Extend/4DC Make sure that the Main Application in HDHomeRun Setup is set to Other:ATSC/QAM or Other:DVB-T/DVB-C while you are running the scan. It can be changed back to the standard NextPVR option once the scan is finished.
For HDHomeRun PRIME, make sure that you are running a firmware version of 20130328 or newer and that you have completed a channel scan in HDHomeRun Setup.
Check your firewall configuration and make sure that the NextPVR, NRecord, and NDigitalHost programs have full network access.
In the codec configuration area in NextPVR, make sure that you have selected decoders for MPEG2, H.264, and AC3.