Hi, I am experiencing the same error. I believe it may be due to the quality (or noise) of the reads.
The raw data are 16S DNA sequences (from Illumina MiSeq technology).
In Step 4 the análisis stops.
seq_process_details.txt (2.9 KB)
I am attaching a PDF that may be helpful…
MicrobiomeAnalyze.pdf (107.4 KB)
Thanks in advance
Deb!