AUDIO not Working from VOIP.MS

Hi, I have a variety of phone devices in different locations that have been connected to my FS server working great for YEARS. We switched from VoipInnovations to Voip.MS. I have triple checked the configuration matches the FreeSwitch article for VoipMS. I immediately started getting INTERMITTENT one-way-audio. The only change is FS was the new external gateway and routing path for outbound calls. I have switched one location to connect directly to VOIPMS with their CISCO phones. We get the same problem. Occasionally a call works fine. Other times it is one-way IN, others it is one-way OUT. HELP!!!! Regards, Sean