When performing a conversion from an on-line video to an animated GIF there is a limit to the allowed size of the animated GIF, which is based on the Total Resolution. The Total Resolution is calculated by multiplying the width and height of the animated GIF against the number of frames and the duration of the animated GIF. For instance a 150 by 150 pixel GIF with 3 frames per second lasting for 5 seconds, would have a total resolution of 150 x 150 x 3 x 5 = 0.32MB
To get animated GIF's with a larger Total Resolution, upgrade to one of the paid package.
Use this total resolution calculator to see what package you will require.