The exact same stalls you tried to use with the other EVs? or a different location (operated by CYC / CPS)? I would have little faith in the latter ...
I've heard plenty of stories that more modern cars have failed to work with older CCS pumps. There seems to be a fair bit of evidence that the modern cars adhere correctly to the standard, and older pumps might not (i.e. whatever bug there is just didn't come to light at the time, or the standard has been updated but not the pumps). Probably to do with hand shaking [to initiate the charge] and/or safety enhancements.
I haven't been following it closely recently, but several months ago there was talk of Ecotricity upgrading their pumps to conform to the newer standard ... and it not happening. May well be that has happened by now ... but wouldn't surprise me if it was hit-and-miss at a given random CCS pump.
I would hope that somewhere where a Model-3 charge has been successful that any Model-3 would be able to charge there, but that certainly wasn't the case for all (for example) iPaces - some could charge at pretty much any CCS, and some couldn't charge at any,a nd most had problems with given brands (such as Ecotricity).
Worth a look on Plugshare / Zap-Map to see if any Tesla owners have left comments (either success or failure) as an indication of likely outcome. You probably need to use both APPs as people are only likely to leave a comment on one, or other, and comments are usually quite sparse - and thus can be quite old and possibly no longer relevant as a result.
Tried both the failed chargers again today and both still failed to charge. I had a look on Zapmap and Plugshare and have found another charger where a guy with a new m3 had successfully charged so will try it tomorrow.