[ktho17]

My phone can send texts, recieve texts, send calls but it cannot recieve calls. They go straight to voicemail. I have already tried turning off call forwarding

My carrier is At&t
The phone is rooted
Running:
Android 5.0.1
Sense 6.0
Viper 4.3.0 rom

[IAmSixNine]

Contact ATT and see if they can help you.
If you can send / receive texts and send calls then it sounds less likely your device unless you have an app or setting telling it to not answer calls.
If you have ruled that out then it maybe a network issue where incoming calls are not going to your device or being rejected by your device.

[srkmagnus]

I would suggest making sure you have the correct APNs setup to use AT&T's voice services. Since you are using a ROM the APNs might be the issue.

Otherwise, try a clean install (factory reset, flash ROM, and boot). Let us know how that goes.

[orella]

this is not a problem with your phone, contact AT&T and see what they say