When I do not choose a specific S3 bucket to use in Settings>WPLMS S3, I can normally upload files to either of the existing buckets and use them. However, when I try to specify a bucket to use in Settings>WPLMS S3, I get this error in the upload window after the upload (I can browse the list of existing files in the bucket though):
"There has been a critical error on your website. Please check your site admin email inbox for instructions.
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I tried my luck in different buckets, used both default s3.amazonaws.com hostname and hostname/endpoint with region indicators (which are both US regions), none of my tries succeded. Note that I created an IAM user for a specific bucket in my account for other purposes as well. But don't think this should be a problem (1) as I can upload files when I do not specify a bucket in the settings and (2) I encountered the same error when I had only one bucket.
I want instructors to see and use only one bucket. So would like to use/show only one bucket for instructor uploads. How can I fix this issue?