Issues mining Luxcoin with CCMiner

I apologize if this is the wrong place to post this or if I make some other obvious error, but I am new to mining anything and want to mine lux coin. I downloaded CCMiner and set the miner up to mine on the Altminer.net pool.

I have two issues that I will describe to the best of my ability below:

1. My second GPU (both are 780ti's) almost always is "rejected" because it is an "invalid share". This happens probably 95% of the time that it is running.

2. The program seems to crash whenever it starts to mine a different block than when I started the program. I don't know what error message is displayed because the window closes as soon as it crashes. If someone knows to stop the window from closing after the program crashes I can provide an error message.

I am using ccminer 2.2.2 and have the latest drivers for my GPUs.

Thanks in advance