Hi Michael,
Danger - please do not run the commands listed in this "detail" section
unfortunately, the error message is not too speaking. Thus, my first step would be to modify SEPP to report a little more verbose error messages. You should find the according run-sepp.sh script in /Users/mish0397/miniconda3/envs/qiime2-2018.4/bin/run-sepp.sh
Use your favourite text editor. Search for the line trap cleanup EXIT and comment it our, i.e. add a # in front of the line. Re-run qiime and hope that the error message is more verbose.
How many CPU cores do you have on your system? Looks like you specified to use 3 threads. You could try to reduce to just 1.