Virgin media and 02 logins not working...!

I've been trying to access my ntlworld email since friday and keep getting the below. That happens on all devices, different computers and phones and different browsers:

I also tried to log in to my O2 app and have the same error message. Can you help?

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The requested URL was rejected. Please consult with your administrator.

Your support ID is 2b8f479f-02ba-450a-9e61-4e22c5a961d4

Error 403 - Forbidden

F5 site: pa4-par