Use easy-rsa to set up a self-signed certificate authority for Central

[dmenne]

Best check these:

Get Blank Forms from ODK Collect not working on local ODK central server

Probably you can find an asnwer on one of the following posts:

And the the official comment that self-signed certificates are not tested, so you are on your own:

Selfsign certificate with latest Central

We don't test with self-signed certs. Central is probably OK with a self-signed cert, but Android, and thus Collect, is probably not. What happens when you try it?