Hi @Panuwat_S ,
Please check whether the file content of the 'create file' is empty in the run history.
Could you please post a screenshot similar to this?

In addition, you can try to add a 'Get attachment' to get the content of the attachment.
I did a test for your reference.
In my scenario:

My OneDrive File could be open:

Best Regards,
Sunshine Gu