Refer to the exhibit.

In a Cisco Unified Contact Center Enterprise deployment, an agent is having trouble logging in to
the system. In reviewing the CTI OS log file, the error message has been found in the log. What is
the likely cause of this error?

A.
The agent’s phone is not associated with the PG User.

B.
The agent’s password was typed incorrectly or is not valid.

C.
The agent’s CTIOS client is running a lower version than the CTIOS on the Peripheral
Gateway.

D.
The client cannot communicate with the CTIOS on port 42028.