Welcome to Vodafone Community
Two days ago i changed my contract to sim only. when on data it won’t let me download mail or login to webmail.
however when on wifi i can connect to both.
its giving me a certificate error. surely this would be the same on wifi. any help appreciated
Changing contract account type shouldn't really affect what you can access.
My suggestion is to double check the settings and if necessary delete the email account from your phone and reset it back up.
Perhaps try another email app too.
Current Phone > Samsung Note 20 Ultra 5G - SM9860 Snapdragon.
Samsung One Ui 3.1 / Android 11.
Please see this previous thread https://forum.vodafone.co.uk/t5/Android/Not-receiving-emails-over-4G-when-WiFi-works-ok/td-p/2600895. There is a reply from @hrym answering a post with the same problem.
As @hrym mentions wait for the Team to get to the thread, they will be able to investigate this for you.
@Alex it might be worth mentioning there has been no reply to the linked thread and the OP still needs help as of the 22nd November.
I finally got this solved by having the SecureNet software removed from my account. This solved the problem immediately.
Given I had asked when I transferred to the new contract not to have it I was increasingly frustrated. A nice gentleman from the Egypt office removed it and within 2 mins it was working as expected.