The short answer
"Send my calls to my cell" can mean two different mechanisms, and choosing the wrong one is the commonest cause of "it only forwards sometimes." This page is the extension's own forwarding. The other mechanism is Office Anywhere.
The four settings
- Call Forwarding Always. Every call to the extension goes to the number or the mailbox you name. From a phone:
*72and the number to turn it on,*73to turn it off. In Webex: the gear icon, Calling, Call forward. - Call Forwarding Busy. Only while you are on a call.
*90on,*91off. - Call Forwarding No Answer. After the extension rings a number of times without an answer. The count is in rings, on the Settings tab.
*92on,*93off. - Call Forwarding Selective. Rules: forward when the call arrives inside a schedule, or from certain numbers, to a destination per rule. This is the one that carries hours, and it is how "after hours, send my calls to my cell" is built on an extension.
Two more ring outside numbers without forwarding: Simultaneous Ring rings outside numbers at the same time as the extension, and Sequential Ring rings the extension first and then up to five numbers one after another. Each carries one schedule for the whole feature.
All of these are cards on the extension's Settings tab in the portal. A card that is not there yet is added from the + Features panel on the same page.
Which calls they cover
The extension's forwarding fires on a call that arrives at the extension directly: someone dialed the extension or its direct number, a menu key sent the caller there, or a hunt group handed the caller on to it. It does not fire while the extension is simply ringing as one of the members of a hunt group or a call center. So a receptionist whose calls come through the front-desk group will find that forwarding "only works sometimes": it works on direct calls and not on group calls.
When the cell has to ring on group calls too, the tool is Office Anywhere, which makes the cell part of the extension on every call it takes.
Which settings have hours
Call Forwarding Selective, Simultaneous Ring, Sequential Ring, and each Office Anywhere number carry a schedule. Call Forwarding Always, Busy and No Answer do not: once one is on, it is on around the clock. A cell that rings outside the hours you set is explained by whichever setting on the extension carries no hours, and, when everything on our side is off, by the Webex mobile app, which has no hours of its own. For that last case, turn off Webex notifications on the phone after hours rather than signing out; signing out also stops the app taking business calls. See schedules.
Forwarding to voicemail
Call Forwarding Always can point at the extension's own mailbox, which is how "send everything to voicemail today" is done in Webex with one switch. To send callers into a colleague's mailbox, forward to *55 followed by their extension.
Forwarding to a number abroad
An overseas destination is entered the way it is dialed from the US: 011, the country code, then the number, with no plus sign. Forwarding abroad is a separate switch on the account that is off until you ask for it, and international minutes are billed at the rate on the pricing page. See extra numbers, caller ID, and international calls.
Do not disturb
*78 sends every call straight to voicemail and *79 turns it off. The Webex app does not show it, so an extension whose calls all go to voicemail while the app says Available is usually this.