I'm getting multiple reports from the branches I have upgraded to v15 that several times a day the softphone client loses connection to the deskphone. A user will pick a number or manually enter one, press Enter or click Call, and nothing happens. If the user pulls the POE cable and re-boots the deskphone, it works until next time. Also, if I re-boot the handset from the server management interface, it works until next time. I have tried uninstalling and reinstalling the client but it seems to make no difference. The deskphones are Yealink T22s. I updated firmware to latest with the v15 release.