I have seen this issue posted before on the forums but I could not find an answer. The attempt to backup to the S3 gives the error that the secret access is wrong. I have one WordPress plugin that works, testing another called UpdraftPlus that gives the same error as the Virtulmin S3 backup. I also use a Firefox tool that has no issues accessing the S3 account. Very mixed results. There are only two files plus the bucket name to fill in. I know the access values are correct and have tried bucket names with and without a slash and in the case of UpdraftPlus, it will create a bucket if it is not there and that does not work either.
You would think it would be foolproof. Any suggestions Mr. Wizard?