There are several things that can cause this.
One side of garage door higher than other side.
If it was opening too quickly move it to the next lower hole.
The mark on the shaft should be about 1 4 above the mark on the drum as shown.
Sometimes your garage door will close on top of an object and the cable on that side will pop off.
Vise grip the shaft.
If the gap under the door is less than one inch make the marks 1 8 apart.
Garage door crooked and the cable came off.
If the door was closing too quickly move the spring to the next higher hole on the bracket.
This can happen when the door has shifted to one side causing it to appear uneven.
In the next series of steps you will move your ladder to the other side and climb up to the left cable drum.
When this happens you need to shift it back into position.
Retest the door balance as you did in step 1.
Check to see if one door hangs lower or higher than the other.
Run your hands between the front corners of your side by side refrigerator doors to determine if the doors must be aligned.
The most simple and common is door shift.