valid PDF file getting "not a pdf file missing %%EOF" while reading

[giovapanasiti]

I have this valid PDF which I can read and I can even parse it with nodejs. When I try to read it I get this:

not a PDF file: missing %%EOF

Any idea?

[miguelpragier]

I know it's too late, but for other's reference:
I solved here passing the correct/exact file size in bytes:

    f,er4:=os.Open(targetDoc)
    fmt.Println(er4)
    fl,_:=f.Stat()
    r, er2 := rscpdf.NewReaderEncrypted(f, fl.Size(), func() string { return "" })