Some services require another number
A retailer, distributor, library, journal or other service may require an ISBN, DOI, ISSN, ISMN or another identifier. An SPSN does not override its rules, and the service may choose not to accept an SPSN.
Check the current requirements of every place where you plan to sell, submit or list your publication.
It is not copyright registration
An SPSN does not create or prove copyright, authorship, ownership or permission to publish. You remain responsible for having the rights and permissions needed for the publication and the information you submit.
It is not government approval
The Self Publishing Serial Number Project is an independent service operated by Written Word Print and Publishing FZC. An SPSN is not government registration, a content rating, an academic review or an endorsement of the publication.
Acceptance is not guaranteed
The SPSN system provides a permanent number and public page. It cannot require another company or organisation to recognise or use that number.