Email works fine on wifi but not on 4G

[#1]

Hi all, hope someone can help.

I have an Iphone using Giffgaff PAYG.

My email works perfectly when connected by wifi, but when trying to use 4G away from home, I can receive emails but not send.

I have set up a secondary server to Plusnet and when the phone checks it, everything comes up ok.

When I try sending an email I get the message "Server rejected recipients addresses".

I know that they are correct because they get emails when sent on wifi.

Have tried everything I can think of, any suggestions most welcome.

Geoff  

[#2]

You will need to set authentication on the outgoing server in order to use it when not on a plusnet connection 

See the guide here https://www.plus.net/help/email-guides/how-to-set-up-plusnet-email/#what-other-settings-do-i-need

You can leave authentication set permanently, it will still work when on a plusnet connection

[#3]

Thanks. It's wierd.

Have always used password to authenticate. Rebooted the phone this afternoon and the 4G connection from Giffgaff to Plusnet is now working fine.

Thanks again.

Geoff