Aspose Java PDF to PDFA conversion error message

We are getting the following stack trace when trying to convert PDF to PDF/A.

Caused by: com.aspose.pdf.internal.p230.z158: Requested font type subsetting is not supported.
at com.aspose.pdf.internal.p230.z461.m18(Unknown Source)
at com.aspose.pdf.internal.p63.z32.m31(Unknown Source)
at com.aspose.pdf.internal.p63.z29.m1(Unknown Source)
at com.aspose.pdf.internal.p64.z6.m1(Unknown Source)
at com.aspose.pdf.internal.p65.z1.m1(Unknown Source)
at com.aspose.pdf.FreeTextAnnotation.m1(Unknown Source)
at com.aspose.pdf.Annotation.updateAppearances(Unknown Source)
at com.aspose.pdf.InternalHelper.m1(Unknown Source)
at com.aspose.pdf.internal.p110.z8.m1(Unknown Source)
at com.aspose.pdf.internal.p110.z8.m2(Unknown Source)
at com.aspose.pdf.internal.p110.z9.m13(Unknown Source)
at com.aspose.pdf.internal.p110.z8.m1(Unknown Source)
at com.aspose.pdf.ADocument.m1(Unknown Source)
at com.aspose.pdf.Document.m1(Unknown Source)
at com.aspose.pdf.ADocument.convertInternal(Unknown Source)
at com.aspose.pdf.Document.convertInternal(Unknown Source)
at com.aspose.pdf.ADocument.convert(Unknown Source)
at com.aspose.pdf.Document.convert(Unknown Source)

We are using version 17.9.

This is a process converting incoming PDF files, so we don`t know what fonts might be referenced. Can you advise what causes this exception to be thrown , and what we would need to do to prevent it?

Thanks

@james.cross

Thank you for contacting support.

Please upgrade to Aspose.PDF for Java 18.7 in your environment and if the issue persists, please share a narrowed down code snippet and source PDF file with us so that we may try to reproduce and investigate it in our environment.