This can be several things, but if you are using Windows it could be an issue with Internet Explorer. Internet could work fine on other browsers like Chrome or Firefox but our Secure Testing app uses some of the settings from Internet Explorer so if there is malware or bad settings in IE, then the app may also not work well.
If you're having issues like this open internet explorer specifically. Windows 8 & 10 have a new version of IE which is called Edge. This isn't the same thing and your computer also still has internet explorer. Go to your start menu and type in internet explorer to find it.
Once open, go to emstesting.com and try to log in. If you get pop ups or errors it may be something on your internet explorer that is making both it and Secure Testing App not work. You can try using anti-malware or anti-virus programs to clean it up, or you can 'reset' internet explorer which brings all of the settings and add-ons back to default state. This won't get rid of bookmark but it will erase your history and any auto-login passwords that are saved in the browser.
To reset internet explorer:
Tap or click the Tools button , and then tap or click Internet options.
Tap or Click the Advanced tab, and then tap or click Reset.
In the Reset Internet Explorer Settings dialog box, tap or click Reset.
When Internet Explorer finishes applying default settings, tap or click Close, and then tap or click OK. You'll need to restart your PC for these changes to take effect.