AWS Lambda UnknownError when go to Functions section and create Function

Hello.

Does the IAM user you are using have the necessary IAM policies attached to operate Lambda?
Also, if your AWS account is managed by Organizations, please check that Lambda operations are not prohibited by SCP.

There may also be a problem with your AWS account.
Therefore, please contact AWS Support by opening a case under "Account and billing".
Inquiries under "Account and billing" can be made free of charge.
https://docs.aws.amazon.com/awssupport/latest/user/case-management.html