Solo mining Litecoin from source code

[Ganon5]

Hi,
I'm trying to understand the Litecoin source code so I compiled it and started my own coin but I am unable to mine.
I'm getting the error "500 internal server error" when trying to mine with cpuminer
I configured the litecoin.config correct and checked it multiple times you have to note that I am unable to mine on the Litecoin chain aswell
I hope someone can push me in the richt direction