Hello @Y-aka ,
I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer.
Issue: Azure Machine Learning - Creating Error, Compute Instance in West Europe Region
Solution: Instead of creating the Compute Instance, created a Compute Cluster, after that were able to use it successfully. Also, checking the workspace details and tried with other resources was valuable, and it helped to troubleshoot in the right direction.
If you have any other questions or are still running into more issues, please let me know.
Thank you again for your time and patience throughout this issue.
Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.