PDF Signature With Timestamp Embedded Showing Invalid

We are trying to embed Timestamp signature as a unsigned attribute in CMS format but after stamping signature in PDF, PDF viewer giving the signature includes an embeded timestamp but it is invalid message.

We have used internal TSA service (self sigined) TSA and bouncy castle API for crypto and signing operations. But don't know what is happening with pdf. Could anyone know why pdf giving this message. Find attached hello_signed.pdf file.

Please help to fix this issue.