SD card not initializing sometimes

I'm using an SD card module from AZDelivery (here). Sometimes (every 10-15 time) it's not initialized when I execute:

while (!SD.begin(10)) {
    Serial.println("Card failed, or not present");

The error "Card failed..." is printed in an endless loop then. The L led is on too. It's strange because if I touch the contacts from the SD module it stops printing the error, the L led turns off and it works. I tried some things with resistors, but this seemed not to work better. I am using an Arduino nano. I tied with the normal SD library and the Sdfat library.
SCK is connected to Pin 13
MOSI is connected to Pin 12
MISO is connected to Pin 11
CS is connected to Pin 10

Try to pullup MISO to VCC with about 50K Ohm. Solved my Problem.