SiliconDust tuners not finding any channels within NextPVR

[YYZ]

I am using NextPVR v3.2.9.

I have four SiliconDust tuners (two HDHomeRun DUAL tuners) which have all had their firmware updated to the latest version.
If I use the HDHomeRun QuickTV app, all four tuners are working fine and I can view all the same digital channels I can see directly on my TV.
(I have an antenna, not cable.)

NextPVR recognizes the devices but cannot find ANY channels when I scan for them.
I have tried selecting both ATSC and QAM, but neither can find any channels from within NextPVR.

Can anyone provide any details?
Any help is appreciated. Thanks!

[pcostanza]

Check that your firewall allows HDHomerun permission.

[YYZ]

Actually, HDHomeRun already had firewall permissions.
But NextPVR didn't so I added it and that solved the problem!

Thanks for the help!

[sub]

Remember to add permissions for NextPVR.exe, NRecord.exe and NDigitalHost.exe