Animated GIF with Grey Background?!

Hello,

I am exporting as Animated GIF (through Media Encoder) and originally my animation is with White background but when I export it as GIF the background becomes grey. How to fix this?

Regards

EDIT: I fixed the issue. I opened the GIF in Photoshop and then Saved it for Web. The background is as of the original video, not a grey one. Hope I can be useful for someone.