no sound in certain sampler tracks

i have created a very large project with almost 200 tracks.
the basis consists of audio segments which then i also i loaded into sampler tracks further down.
all the audio tracks work, but only some of the sampler tracks work (ofc with midi that controls them).

now some of these samplers work well, but quite some others inexplicably do not work at all, no playback at all by any keyboard.
the samples are not even triggered by me playing their little control keyboards.

the problem is the same procedure i use for these tracks does work indeed and well with a part of the samplers but refuses to work with others.

can it be i am using/reusing the same material too often, or what setting do i miss?

Check your MIDI channels on the ones which are not working.

thank you for helping!
yes i did check midi channels, they should receive all (as do the other completely similar sampler trackss) but half of these tracks simply do not react.
i am truly at a loss…

Sometimes, MIDI does not work if it is being shared across several tracks, same channel. The DAW selects one over the other track.

Internally, how many MIDI channels can you assign? Usually I have found most DAWs only do 16 internal MIDI “buses” or channels.

the problem is with the Nuendo 10.3 native sampler tracks.
i now made a workaround by loading some samples in Halion others in Backbone, and then it all works perfectly
to me it is still a mystery why with the same settings these samplers do work while the native sampler tracks do not

as to MIDI channels, i normally use 1 channel per track, and indeed since the MIDI played is only in a particular track, such tracks can all be set to 1
afaik i can assign A-D each 16 so 64 channels max