When we're trying to open crm portal with chorme or edge but we aren't seeing anything, we are seeing just an empty page. But we try to open with IE, portal is working, main page is opening. In main.aspx, I found a this code. 

<meta http-equiv="X-UA-Compatible" content="IE=8">

I though it worked just IE because this code, I edited, I changed but it didn't work. So what do we need to this? Also we installed UR 6 last. Do we need to upgrade?