SIP VOIP Phone can't hear Caller

Question: Why is my #VOIP Phone not allowing me to hear the caller?

Login to See the Rest of the Answer

Answer: If you have access to the #SIP Server, check to see if you have 
pedantic=yes flag in the Sip.conf file, if you do then comment it out as shown below
;pendantic=yes and reload the core reload.

After the reload happens, test again and see if the problem persists.