Email apps such as you are using on your iPhone often come back with default error messages so the "incorrect password" error message does not necessarily mean there is a problem with your password.
In reality when the app has failed to connect to the VM email server it just reports the most likely reason for that.
Just to troubleshoot this a bit further to find the real problem::
If you can send emails when using the VM webmail service on the VM website and from your iPhone when it is connected via your mobile date network then you need to check whether your VM IP address has been blocked.
You can check that by opening up a browser (you need to be connected to your VM wifi, not your mobile data) and then:
Your address may well be listed on the Spamhaus PBL but that is to be expected and is not a problem.
If your IP address is reported as appearing on another blocklist then post back here and advise which list or lists.
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Thanks for using the forums to get this issue with your Email looked into, I am sorry if this has been causing some frustration.
Have you been able to follow Coenoby's advice?
Has it helped to resolve the issue?
if not, I have a helpful link here - Virgin Media Email Issues - Which may help further.
Please let us know what the situation is now.