We couldn't find the record that lets on-premises users authenticate to the cloud for instant messaging and web conferencing ...

We couldn't find the record that lets on-premises users authenticate to the cloud for instant messaging and web conferencing for domain '{0}'. You have to set up a specific entry in DNS to make this work. The missing record is type SRV. Click on the link 'get help fixing this issue' in the actions pane located on the right side of the screen for assistance.