Hi Ryan,
sorry for the late response. Unfortunately, SEPP is very silent if it runs into errors. This is caused by the bash script itself which is engineered to NOT leave temporary files across several compute nodes when failing.
You might want to change this behaviour. Take a look into this post: Run-sepp.sh returned non-zero exit status 1 - #2 by Stefan But make sure you personalize this path to your needs /Users/mish0397/miniconda3/envs/qiime2-2018.4/bin/run-sepp.sh