RuntimeError: clEnqueueNDRangeKernel failed: OUT_OF_RESOURCES in fitting with CHARMED_r2

Dear Robbert 
I would like to fit a diffusion signal from a rat with the CHARMED_r2 model. Unfortunately, it always appears the 
"RuntimeError: clEnqueueNDRangeKernel failed: OUT_OF_RESOURCES", regardless of the number of processed voxels (10000, 5000, 500, 10, 1). My GPU is A6000 ...
Thanks for any suggestion
Best
Stefania Oliviero