Remote Extension Drops Transfer Calls

Hello to the group,

I have a FreePBX system that we use for our Business phone. Several employees also work from home occasionally and use remote extensions at their houses to access our phone system. One employee’s phone will dial any extension on the system just fine (4-digit extensions on our system). However, when she attempts to transfer an incoming call to another extension, after dialing the first two digits, the phone starts to dial the extension and says the extension is unavailable.

Can anyone point me to the configuration issue that I might have? I have looked over everything and do not see an issue. As far as I know, all the other remote extensions do not have this problem.

Possibly the “dial plan” (often called “digit map”) in the device is incorrect, but she normally bypasses it by dialing on-hook, which is not an option when transferring.

Phone make/model (or softphone/SIP app platform and version)?
Using transfer key, or DTMF codes such as *2?
Provisioned by EPM or manually?
Range of extension numbers?