Nighthawk CM2050V voice issue

[MJ111]

I have Xfinity and Nighthawk CM2050V cable modem with voice.  It is less than one year old.  I've lost dialtone for my phones.  When I log in to the cable modem, it shows voice is ready and on-hook. Have tried connecting a phone directly to modem and there is no dial tone.  Called Comcast and they said when they call number it rings and then goes to voicemail and they are not seeing any errors.  So they think it is problem with the modem.  Have rebooted modem and rechecked all connections to no avail.  Anyone else having this problem and/or know if there is anything I can do to correct the issue?  Thanks

[Kitsap]

What type of phone are you connecting directly to the modem?  A newer cordless base station or etc?

If you have or can borrow an older tone dial handset try that. 

Some of the newer base station type of phones require special settings to connect to VOIP adapters.  If you have the manual for your phone, check in there.