The SIP subscriber has been configured in U1911, but 3rd party IP phone cannot register to U1911 using the SIP user.
There is a soft argument parameter set on U1900 series, which allows or denies the registration of 3rd party IP phones. Depending on the version of the U1900, the default value of the parameter is different.
Check the value of the parameter:
show softargu configinfor id 286
- Set the softargu parameter to 0 in order to accept 3rd party registration and the issue is solved:
config softargu type 286 value 0