wplms s3 Not working on 4.X demo

Well we checked your site and found that it is upgraded to v4 wplms version with which wplms s3 is not compatible yet . With V4 version it will throw error right now. We are working on wplms s3 itself these days to make is compatible with V4 version. If your site is live we would suggest you to either restore v3 version from backup or revert to V3 using this tip : https://wplms.io/support/knowledge-base/reverting-from-4-0-to-3-x/

This is what I got in e-mail from WordPress when this issue occured. "Howdy! Since WordPress 5.2 there is a built-in feature that detects when a plugin or theme causes a fatal error on your site, and notifies you with this automated email. In this case, WordPress caught an error with one of your plugins, WPLMS S3. First, visit your website (https://learngah.com/) and check for any visible issues. Next, visit the page where the error was caught (https://learngah.com/wp-admin/media-upload.php?chromeless=1&post_id=110&tab=wplms_s3) and check for any visible issues. Please contact your host for assistance with investigating this issue further. If your site appears broken and you can't access your dashboard normally, WordPress now has a special "recovery mode". This lets you safely login to your dashboard and investigate further. https://learngah.com/wp-login.php?action=enter_recovery_mode&rm_token=37hEeq0POedILMUriz69Bn&rm_key=8njqNn7DIVcNp5wdLEzuEq To keep your site safe, this link will expire in 1 day. Don't worry about that, though: a new link will be emailed to you if the error occurs again after it expires. When seeking help with this issue, you may be asked for some of the following information: WordPress version 5.7.1 Current theme: WPLMS (version 4.097) Current plugin: WPLMS S3 (version 2.3) PHP version 7.2.34 Error Details ============= An error of type E_ERROR was caused in line 192 of the file /home/siltchco/learngah.com/wp-content/plugins/wplms-s3/includes/vendor/aws/aws-sdk-php/src/WrappedHttpHandler.php. Error message: Uncaught exception 'Aws\S3\Exception\S3Exception' with message 'Error executing "ListBuckets" on "https://s3-us-west-2.amazonaws.com/"; AWS HTTP error: Client error: GET https://s3-us-west-2.amazonaws.com/ resulted in a 403 Forbidden response: AccessDeniedAccess DeniedRCZ2RS (truncated...) AccessDenied (client): Access Denied - AccessDeniedAccess DeniedRCZ2RSYDPANGZF9FmkPSMZWUnisIegm6O2j/09JdTcTyb4lMA3ggDUyUove/I0vop9o/pJSIj/v2LXUDDLHjG0waIxs=' GuzzleHttp\Exception\ClientException: Client error: GET https://s3-us-west-2.amazonaws.com/ resulted in a 403 Forbidden response: AccessDeniedAccess DeniedRCZ2RS (truncated...) in /home/siltchco/learngah.com/wp-content/plugins/wplms-s3/includes/vendor/guzzleht"

For Your Information: Amazon S3 crednetials are 100% OK and WPLMS S3 configured/showed settings as "Settings Saved" at the end of the process.