WebGL is common issue with browser games. It can be minimized with the correct optimization, so I hope Plarium will do something in future. In the meantime, you can solve it by following the steps below. You basically need to increase the memory cache of your browser. After following these steps either the issue will be completely fixed or at least you will receive webgl error less frequently;
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Internet Explorer.
Open Internet Explorer
Click Tool icon (Gear icon upper right of the browser)
Now Select Internet Option
Below in Browsing History and click on Setting
Now a window will appear
In Temporary Internet Files select automatically and write the size of memory you want to allocate at least 256 (1= 1MB) or more if you have lots of free storage.
Click OK and save your changes then click OK/Apply again to close the windows.
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Mozilla Firefox.
Open Firefox
Click on Tools >> Options >> Advanced
In “Cache Web Content” select “Override automatic cache management.”
write the size of memory you want to allocate at least 256(1=1MB)
Now click on OK to save the setting
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Google Chrome
Right Click on the Google Chrome icon in desktop
Select properties
Properties >> Shortcut Tab
Below find Target and click inside the box
Now press “End” key on the keyboard and give space before entering the given code below.
Now copy and paste this at the end: -disk-cache-size-1000000
Click OK to save the setting.