Hi nothappywithvm,
Thanks for taking the time to contact us via the Community. It's lovely having you on board with us in the Forums. ⭐
We're sorry to hear you're having an issue accessing your emails. The forbidden error will only usually come up if you've not set up the multi-factor authentication. You'll need to ensure you've set this up in order for the email account to unlock.
Please log in to My Virgin Media here. It should automatically prompt you to update your log in email to a third party account. If it does please follow the on screen prompts to do this. If it doesn't then click on Account settings > Virgin Media Mail settings > scroll down to the App password section and click the Generate new App password button.
You should get a pop up message asking you to verify your email address and you'll need to use a 3rd party email address to continue. You'll be sent a one time passcode to enter on the next page to verify it's you. Once verified you'll then be given an app password which will look something similar to: mail-horse-yellow-panda and you should note this down.
To get things working on an email client or app again, wait for a minimum of 2 hours (this is to allow the account to unlock) you will need to enter the new mail password in the settings. This will allow your emails to load again. In some cases, you may need to remove the email account from the mail client or app completely and re-set it up as fresh. If this is the case for you, please ensure you use your VM email address as the username and the newly generated app password.
These changes have been put in place as Multi-factor authentication (MFA) is now required. Just as a side note, when logging in to My VM, you will need to use the third party email address as the username and your original My VM password.
Please let me know how you get on and apologies for the inconvenience.
Thanks,