Hi @Kayla Stikeleather ,
Unfortunately, it is not possible currently, as the "error message" is implemented in the source code. Apparently, the Dev Team hasn't granted us the settings/policies to customize it.
I would suggest letting your customer send feedback to the Dev Team to request this feature. Feedback can be sent in Microsoft Edge at ··· menu --> Help and feedback --> Send feedback.
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Best Regards,
Shijie Li