[Smush Pro] Smush does not allow me to upload images over…

Hi there,
Looking for use Retina images on my website, I have entered 4096px (2x) size on Smush’s Image Resizing feature. When I upload any image over 2500 px, the process get interrupted by the following error:

Post-processing of the image failed. If this is a photo or a large image, please scale it down to 2500 pixels and upload it again.

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How can I avoid this bug?