Log in using your NT login information if the router is online.
Type in sh port 1/1/7 (if SAR M) or sh port 1/2/7 (if SAR F). The port should be Admin State Up and Oper State Up.
If admin is down, turn up the router port using the configure port 1/2/7 no shutdown command for a SAR F, port 1/1/7, if it is a SAR M.