You are now facing this issue which i discussed here: Dremio ebs volume snapshot fail - #10 by VahagnBleyan
The snapshot is timing out since its taking more than 5 minutes from the AWS side and we have a 5 minute timeout for the snapshot. If you can somehow take a manual snapshot at first, the successive snapshots will work fine.
This issue has been resolved in 18.0 where we have increased the timeout and also provide a flag to configure it to an even larger number.