I faced the same problem. Did you solve it?

Here are the file extensions allowed per the latest IFS Cloud Documentation.

https://docs.ifs.com/ifsclouddocs/23r1/HandleMedia/AboutMediaLibrary.htm

@matt.watters , We are using IEE and I can’t even browse for a file, it is greyed out.

Hello Gentlemen,

Unfortunately it seems APPS10 UPD11 does not allow attachment of videos.

After the Video media item type is selected, I get a greyed out Browse button too. There is a way to access the Browse function by hovering over the area and right clicking to get the following options

This still does not solve the initial problem, however. As you can see the allowed file types only show Image file types in the screenshot below

For a sanity check, verified that the image, text and audio file types can be accurately attached.
 

As stated previously by Matt, all listed file types are supported including the various video formats.

Suggested Workaround - using document attachments rather than media attachments for videos. Since the only video file type accepted in document management is .mov, we need to convert files such as mp4 to .mov before selected Browse and uploading them to APPS10.

Here are some more screenshots for this workaround:
 

Thanks,
Sayeef