We have recently setup AWS and tried to install qiime2 2018.8. Following the instructions in the qiime2 documentation I changed my AWS region to Ohio and proceeded to try to find the corresponding AMI (ami-04d99b45e6d99e48e) which is 2018.8. I could not find any qiime2 AMIs in the Ohio region. In the N. Virginia region I found only qiime version 1 AMIs. I also have a free-tier AWS account which I also used to try to find qiime2 AMIs currently available in the Ohio region and found none.
I am uncertain why I am not finding any qiime2 AMIs in the Ohio region either by name (qiime2) or by AMI (ami-04d99b45e6d99e48e).