uMap: why do I get 'Cookie “csrftoken” has been rejected.....'?

Any ideas anyone? FireFox Portable, 132.0.1 Win 10 64bit
console message - Cookie “csrftoken” has been rejected because it is in a cross-site context and its “SameSite” is “Lax” or “Strict”. Plus there is a preceding “NS_BINDING_ABORTED” involving the map being loaded. My JavaScript waits until “my” rendering is complete before attempting loading the uMap into the IFRAME.

The uMap is in an IFRAME. It does not appear to affect anything, or I am ignoring things I don’t know I could be using.

It does not report same in Chrome, but there are two different failures to load that are not recognised so must be part of uMap. One is a .jpg

The only post in this parish on the subject reports FireFox problems, and not Crome being an issue (the browser).

bench.mister.red - if it helps to explain the above. (it will become https)

Probably “mixed content”. But without knowing the exact problem, so it’s a shot in the dark.