A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Hi IBN.,
Greetings. Thank you for posting the thread to our community. I understand your concern, it seems you’ve encountered an error message when you try to access a folder in your SharePoint site. I also notice the issue persists even though you’ve tried multiple methods to troubleshoot it. For the situation you’ve encountered, I do understand the inconvenience caused and feel very sorry about it.
Due to this situation, I’m afraid this is a temporarily server-side issue needs to be investigated from back end to find the cause. The support team has higher permission to remotely assist you and collect background logs for the root cause. This is a more efficient way in handling this case for you.
Since you mention you are the admin, I recommend you raise a support ticket to get support by following steps from this link: Get support - Microsoft 365 admin | Microsoft Learn
Appreciate for your patience and understanding. Hope you having a nice day.
Sincerely, Harry | Microsoft Community Moderator