Outgoing to mobile, prompting to press button to connect call.

[tye730]

When the caller dials out to mobile, before the call is connected they are hearing a audio prompt to press a key (3, 5 or 6 random) to connect the call, once you press the number it then rings the phone. (The outgoing call has a few dialling tone before the prompt)
This is happening on soft & desk phones.
Local calls connect like normal.

Any ideas? Using cloud v20