I’ll just jump in.
There’s a demo version of Psyscope Pro - I get the same error as OP, loading the pro demo. The free psyscope works.
I’m no dev, but i think “maxBlockSize” is something that is programmed into VCV core - not configurable by the user. VCVHostFX can dynamically change the blocksize between 1 and maxBlocksize (i think), but that’s not what PSYscope is complaining about(?).