Hi
I hope you have solved your problem after this time but if you Haven't here goes.
What appears to be happening is the print is coming of the build plate after a while!
You don't say what material you are using but I am assuming it is PLA/.
There can be lots of reasons why but the most common is the build plate has become contaminated (grease of your hands??) or the bed leveling is to far from the bed plate to get a good grip.