I am using v10 with the call center modules, up to SP5. This is connected to PSTN lines using a grandstream 4108. I have been receiving reports randomly from customers and internal people saying when reaching the receptionist it does not apply their DTMF input, for example, if trying to do direct extension it does not allow it and acts like no keys were pushed. In other cases they say they are just trying to press an option within the menu. I cannot find anything in the logs so far or in my own tests that show a problem. I know the obvious cause is probably a non compatible DMTF setting but this would seem to be odd for the normal caller. Maybe an issue with the 4108 but I would think it would be all or nothing if so, not let some work and others not. Anyone have any ideas? I am new to 3CX and just went live so could just be me not knowing something simple in the system. Thanks.