Hi,
My challenge has been from ODK collect. It showed an error when I was trying to get blank form which I designed. The error displayed is "attempt to invoke virtual method 'int java.io.InputStream.read(byte) on a null object reference".
Ahh it's ONA so please contact them https://ona.io/contact.html
I have seen an error like that but can't recall now or find it. It's probably something with manifest file (not your responsibility), so you need to ask ONA.