Firstly, check is the browser is supported:Supported Browsers, Platforms and Reference Devices
If the issue only occurs in the mobile device you can use the Browser console to analyze it:
Activate the console F12
Activate the Toogle device Toolbar Ctrl+Shift+M and select your device, and reload the application including clearing cache, (in Chrome you just need to right click on the reload button and select the option "Empty Cache and Hard Reloaded"). As you can see the screen get reduce and simulate the mobile device.
REMEMBER to change the configuration back to Responsive!