UBL 2.1 JSON Validation for Malaysia Electronic Invoicing

I need a professional with expertise in UBL 2.1 standards to check the JSON created by PHP. It’s critical that the JSON meets these standards, particularly in relation to electronic invoicing. The verification process should cover:

- Data fields and format: Ensuring all data fields are correctly formatted and in accordance with UBL 2.1 standards.
- Compliance with regulations: Checking the JSON for conformity with relevant regulations.
- Digital signatures and security: Verifying the integrity and security of digital signatures within the JSON.


I already have my function write, it work for invoice 1.0 , but invoice 1.1 need to add Digital Signature
my code having a for below:
Invalid structured submission.


Please refer to the following link for the digital signing certificate profile: https://sdk.myinvois.hasil.gov.my/signature/#digital-signing-certificate-profile. Your expertise in these areas is crucial for the successful completion of this project.

The project needs to be completed within 1 week. The project should include functional testing to ensure all features work as expected.