See Page 59 infra here: https://back.moogmusic.com/sites/default/files/2020-07/Mother_32_Users_Manual.pdf
There's two possibilities here...one of them is that the clock input might be set to the wrong mode, and the pages above show how to correct that. The other could well be that the Euclidean module is only outputting trigger pulses, and the M32 prefers to see gate pulses, which have a longer duration.
One other point: you won't have full CV control over the M32 from Eurorack without the use of a module such as Erica's MSCALE, as the M32 uses -5V to +5V as its scaling, and generally you don't see negative CV values in Eurorack modules.