When you click the login menu from the Nulab web site, the Nulab JobTracking page opens in a new window. This is a type of manual popup. If you have anti-popup software installed on your computer, sometimes this software will stop this new window from opening.
Most anti-popup software has the option to enter the address of the site(s) that you consider to be safe. The Nulab Job Tracking addresses are as follows, you may add them into the accepted or safe sites location within the anti-popup software.