WhatsApp Web emoji GIF menu not displaying GIFs in Safari

I've got WhatsApp Web set up as a Safari app on Sonoma 14.4. When I try to find a GIF to post in a conversation from the GIF panel in WhatsApp's emoji menu, only grey placeholders are displayed and the green progress/loading bar (above the search box) is continuously animated:

The emoji panel works fine and the stickers panel also appears to be okay.

The issue also happens in the Safari browser (17.4 (19618.1.15.11.12)) itself. I don't have the problem when using WhatsApp Web in the Brave browser.

I don't have any adblock extensions in Safari, I unticked "enable content blockers" in site settings and I'd disabled Little Snitch, but there was no difference.

Any ideas what the problem might be and how it might be resolved?

My device:

• 2023 Macbook Pro 16" M2 Max
• Sonoma 14.4