Bitcoin RPC SSL error
After a bit of mocking about with this problem, I figured the certificate files were in a wrong folder. As I was running Bitcoin on testnet, the directory in which it looks for certificates is different, than on the main net. On the other hand, it loads the Bitcoin.conf from the same place...

The folder bitcoin looks for the certificate in is the folder containing wallet.dat, which for testnet is in .bitcoin/testnet/ folder