unknown error (30) at line...

I have a GeForce GTX 1660 ti and I do 3D imaging

I keep getting this error when processing photos

cudaMemGetInfo(&free_mem-size, &total_mem-size):unknown error (30) at line… (33 to 250 it varies)

this tells me GPU is not freeing memory as it’s working.

HOW DO I FIX THIS PROBLEM

Please help me as I thought Nvidia GeForce was the best in the business and all i’m get is errors