By default the URL after refreshing the web app is a lobby. It doesn't matter if you were in a conference. You will come to this lobby in any case.
This plugin prevents this behaviour and, in case that you were in a conference, it will reload the same conference again.
To load this plugin, download the source code from the Github link here. Once you have this code, move it into the plugins folder of your theme, you should name the folder maintain-url.
Once you have copied these files, open the settings.json file inside of your branding package and add the following code to the plugins array.