Media Uploader opens in post window

I am using WP multisite and recently moved to a new server. Everything was fine re., the media uploader at our previous server so I don’t believe this is a plugins issue.

When I click the media uploader it opens up in the window I am currently editing. If I click it to open in a new tab I can get it uploaded but I can’t insert it (the image uploader doesn’t seem to be connected to the post). I am, however, able to insert a featured image into the post I’m editing, just not into the text of the post.

I am thinking this is some setting at our new host but am not clever enough to figure out WHICH setting and several searches through these forums isn’t pointing me in the right direction. Any guesses?

Thanks!
Dawn
https://www.supportforspecialneeds.com