As iPDFDev suggested here, pass the full timestamp raw bytes exactly as received from GlobalSign to the timeStampResponse parameter.And for the trust problem, try importing the TSA's root and intermediate certificates into Adobe's Trusted Certificates. In the Edit > Preferences > Signatures > Trusted Certificates, Click Import and add the TSA's root and intermediate certificates.

Sometimes,any version incompatibilities between syncFusion, GlobalSign's service, and Adobe reader might cause the error too.