Monaco Error

[Chad Pope]

I am running a KENO6 / MAVRIC calculation. I am looking for some guidance related to the following Monaco error:

ERROR in source sampling:

After sampling the source 10000 times, a position

with the following parameters still could not be found:

unit > 0

region > 0

mixture = 1

count 10000 was in mesh source voxel: 27,28,67

The following data cards precede an = card

This error occurs at different time in the Monaco run. Sometimes on the first batch, but not always. Increasing the number of neutrons in the KENO6 model seems to make the error show up after a larger number of batches, but not always.