Mail attchment Preview not functional in Firefox

[jgrata]

When emails with attachments are viewed in firefox, the preview function does not display the attachment.  It opens the preview window and hangs on "Loading Data" message.

When viewing in Chrome and Edge, the preview function works.

This is true in firefox for attachment types such as image files pf png or jpg and for pdfs.  When an image is attached, the image thumbnail is displayed at the bottom of the message window, but the "show" option results as described above.

Is there a setting in firefox that should be adjusted?

[JohnDoh]

are there any clues in the browser console or network tabs?

[jgrata]

A snip of the output on the console tab is attached.  Other than quirks mode, everything seem normal?

[jgrata]

Here is the snip of the network tab:

[melliw]

Hello all,

I had the same issue. It was caused by enabling the accessibility.blockautorefresh preference on firefox.
I had to restore firefox default behavior to solve it (about:config > accessibility.blockautorefresh to false).