Go to the settings for Microsoft Edge and under Default browser- select Allow for Allow sites to be reloaded in Internet Explorer mode.
Then under Explorer mode pages click on add and then insert the RCS url
Restart the browser and load the RCS URL.
If opening RCS in microsoft edge results in a blank page, there is an option to reload the page in IE mode. From the menu go into "Reload in Internet Explorer mode"
There is an option to always open the link in IE mode