# WebGL - Uncaught TypeError: Cannot read property 'toLowerCase' of null

**URL:** <https://forums.unrealengine.com/t/webgl-uncaught-typeerror-cannot-read-property-tolowercase-of-null/462502>\
**Category:** Platform & Builds\
**Tags:** webgl, unreal-engine, web-browser, question\
**Created:** [March 16, 2020, 12:00pm UTC](https://forums.unrealengine.com/t/webgl-uncaught-typeerror-cannot-read-property-tolowercase-of-null/462502 "2020-03-16T12:00:12Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![TheoT](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@TheoT](https://forums.unrealengine.com/u/TheoT)\
**Post date:** [March 16, 2020, 12:00pm UTC](https://forums.unrealengine.com/t/webgl-uncaught-typeerror-cannot-read-property-tolowercase-of-null/462502/1 "2020-03-16T12:00:12Z")

</div>

Hi!

I have a very simple UE program that I am trying to deploy do my website. I can run it perfectly on my PC local host but not when its hosted on my website. It is deployed there correctly but when I launch I get the error:  
“Uncaught TypeError: Cannot read property ‘toLowerCase’ of null”.

 ![297923-error.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/9/9/2994db1ad0013d1e319e048d8999576cc32f8048.png)

NOTE: I tried with a ‘development’ build, with that it works but not with a packaged build.

Any help please?  
Thank you!