Black screen after flashing custom ROM

[max_dilen]

I recently rooted my Samsung J700F successfully. Installed TWRP custom recovery and then flashed a CyanogenMod with Gapps on it using the recovery. Now, whenever I power on my device, A Samsung logo with model name pops up for 2-3 seconds and then there is a black screen and nothing happens. I have waited for 10-15 minutes, rebooted again, cleared cache partition but nothing works. Please help.