I am trying to host a metadata file and act as an IdP.
To generate the metadata I used the following online tool https://www.samltool.com/idp_metadata.php
After filling out the form and building it, the validUntil attribute is set to be the current timestamp.
When trying to test this metadata with https://samltest.id/upload.php it says expired.
When I increment the year and try again the metadata date doesn't seem to change.
How can create an IdP metadata file that is valid?
You can manually change the validUntil value according with your requirement. There won't be any issue during validation on the aforementioned site.
To verify, I just quickly ran through changing the field value and my input meta-data passed the validation.