Some senders do not like large files.
This can be especially true for JAVA based senders which can on occasion LEAK with large files causing a seemingly random stop or just hanging.
There are cases where you can define extra memory space for a particular JAVA program but you would have to talk to the people where you got the program for specifics.
You can verify leaks by dry testing different size g-code files.
Or if you are trying multiple passes then cut down on the passes so maybe do a set of passes at a roughing setting in one program and then do a second set of less passes at a medium setting in thier own program, and finally doing a short set of finishing passes again in thier own program.
Downside of that method is that if you loose home position at any time it can be awkward to pick up a new home unless you already have homing switches etc.
Another option is to try a different sender as you can choose from so many.
Mach3 and Esticam would not be my first choice for a new user as they are PAID programs.
So until you are more at home with senders and g-code the free ones will often suffice.
I like UGS in particular. It too can be a little tricky about extra large files but for the most it does what I need.
Could you also take a few moments to Learn How To Use The Forum.
It will help you get the best out of the forum in the future.
Other general help and troubleshooting advice can be found here.