Here is possible error:
admin@server1 [~/public_html/]# convert image.png -quality 50 image2.webp
convert: delegate failed `’cwebp’ -quiet %Q ‘%i’ -o ‘%o” @ error/delegate.c/InvokeDelegate/1928.
Supposed ImageMagick already installed then install cwebp
yum install libwebp libwebp-tools -y
Then try to convert your image again
convert image.png -quality 50 image2.webp or cwebp -q 50 image.png -o image2.webp