3351556 - AWS S3 backup with IBM Db2 errors with "Detailed Err = |The AWS Access Key Id you provided does not exist in our records.|"

Starting an online database backup using AWS S3 results in database down. 
First error  "A vendor device reported a media error." is reported in the db2diag.log 
Including a stack output with the following lines.
"The authentication string 1 (e.g. Username, Access Key ID, etc) is not valid."
 "Detailed Err = |The AWS Access Key Id you provided does not exist in our records.|"
Additional information will include
 Vendor Type           = 
  Role                     = 
  Server Name        = 
  Container Name    =
ADM0503C  An unexpected internal processing error has occurred

Db2 LUW IBM
AWS S3
Amazon S3 bucket

S3, Backup, AWS, Amazon, IAM, console, bucket, token, , KBA , BC-DB-DB6 , DB2 Universal Database for Unix / NT , Problem