Hello, @logandeyo
Thanks for reaching out.
Please allow me to add some details regarding your request 
This error means that a client is forbidden from accessing a valid URL. The server understands the request, but it can’t fulfill the request because of client-side issues.
API Gateway APIs can return 403 Forbidden responses for any of the following reasons: Troubleshoot API Gateway 403 Forbidden errors
Also, I’ve tested the ability to upload the files with the Gui and NoGui elements to the same folder with our Demo Settings, and the result was successful 
The endpoint for both elements is the same. However, we will supplementary check this point with our Developers.
The links are unreachable due to the security settings of your bucket 
For the investigation of your issue, can you please share with us the screenshots of your current settings for both elements ( and workflow for them, in case you created it), and screen of the plugin’s settings ( in the plugin panel), where we can find the syntaxis of the keys and region?
Looking to hearing from you soon.
Best regards,