File Format ".gif" doesnt suppoer Error! Pls Help

Hello I wanted to create a gif today 25x25. When exporting it says that the palette has more than 256 colors and error with layers. When I export it anyway the gif when I play it is normal but when I send it on Discord for example it is very buggy and the colors disappear. What do I have to do now to make this message and these errors disappear?

Screenshot_36

Here you can see how the colors are buggy at some frames

Convert your sprite to Indexed mode.