In order to use the web client with Snom DECT M-Series equipment, a few minor adjustments to the 3CX system are required.
Please follow the steps listed here:
Add the desired device to the list of phones supporting UA CSTA M700 and M900, see picture below.
As a result, you will see the Name of the choosen DECT Base, in this case "M700" on the upper right corner of the WebClient page.
Otherwise it will look like that "Webclient".
Note: There is a difference to desk phones.
In this case, your handset/headset will first ring and when you press the OK button the call will be routed to the dialled number.