1 - The plugin installed successfully on 1st attempt
2 - I then deactivated the plugin and re activated it and it has thrown the below error:

The plugin generated 2 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.

The theme I activated is called SYDNEY and its a free theme 

3 - When I attempted to change the theme to another free theme, the wp-admin stops working and a blank white screen appears due to the issue with your plugin

4 - I then renamed the plugin using ftp and the wp admin is working which tells me the plugin is not coded 100% to be consistent. 

5 - As mentioned earlier, the colors and fonts on the plugin output page are not professional and need to be revisited.