Fatal Error after installing webp express plugin

Fatal error: Uncaught : Call to undefined function define() in /home/u540660710/domains/mobilepricez.com/public_html/index.php:0 Stack trace: #0 {main} thrown in?/home/u540660710/domains/mobilepricez.com/public_html/index.php?on line?0

Im facing tha tissue in my website

i have deactivated themes and plugins but it didnt work, i had just installed webp express plugins to reduce my images on my website and after that i got that error.

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