iPhone 4 and 4S

[MIKEHENNESSY]

Hi
I regularly have a problem with my email on he iPhone where it 'hangs' when I try to reply to a message.  It will try for ages and then fail, leaving the message in the outbox.  This only happens when I am outside my wifi network (eg only on 3G network).  I am particularly concerned now as this seems to have caused me to use all of my 500mb data allowance in one day due to the phone constantly seeking to send the message.  As soon as I return within my wifi the message goes without a problem.
Does anyone know what may be causing this?
Thanks.

[RupertTheFridge · Accepted solution]

it will be the SMTP settings for the account. On WiFi your connected to a fixed line internet and using your email providers settings is fine and will work. When connected to 3G your connected to Vodafone. This is why Vodafone had there own .com and 360 accounts in the past so you could use their SMTP settings. Easiest solution now would be to sign up for a free email account such as Gmail, then use the Gmail SMTP settings in place of your email providers, but keep your incoming server settings the same, should work a treat.