Hello there!
I was with this problem somes days when I've tried to integrated SharePoint to CRM2016 (On Premise) and get post of solutions like to add urls in safes sites, add ips, the frame is too little, etcs...
I've read that this error is when the "Url1" is "steal" information to "Url2", so you need put both Url in "Privacy - Let" in "Internet Options".
But I can't put CRM URL because it keep with http:// and not https:// (We don't have the SSL or SLL yet) and I've read that web without https are considerated "No Safes Sites"
My dude is, this error will be solved if we get "https://"?? Or we can keep get that with this change?.
Meanwhile, I'm triying to do all solutions that was gave.
PD: I've my http:// crm in "safe sites", but I can't add it in "Privacy - Let"
Thanks for your time.
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