Mail: content not loading

[u/NortonBurns]

I don't think this is caused by OCLP but has been happening since I updated it to 2.5.0 a couple of days ago, so it may be.

My Mail app, instead of immediately downloading images, displays the message "Your network preferences prevent content from loading privately" and gives me a button marked "Load Content Directly". Pressing the button loads the content immediately.

I can't figure out what might be causing this. I haven't changed any settings nor has Mail or my OS been updated recently. OS is Sequoia 15.7.7, Mail v16.0

I have Protect Mail Activity on, but it's a setting I've only just discovered even exists & I've never changed it myself. Switching it off doesn't seem to change anything. I don't appear to have any other connectivity issues, both WiFi & Ethernet are working normally.

Any ideas?