Hello,
Are you a user trying to program using blocks? Or are you a developer trying to use Blockly on your website?
If you're a user, you should report this error to the application you're using (eg scratch, makecode, app inventor) because we won't be able to fix it :/ No matter how much we'd like to hehe.
If you're a developer, could you provide some more info about the problem? Eg definitions for any custom blocks, any errors you're seeing in the console, and steps to reproduce the error. Once we have a bit more information we should be able to get this sorted =)
Best wishes,
--Beka