Email html rendering/base64?

I'm absolutely mystified. I'm trying to send an html email which looks fine in loads of webmail browsers....but....someone with an IPad which has the apple native email client. says it renders as raw html, as it does in thunderbird.
When I looked at the source the content-transfer-encoding : base64, but an email which looks ok in the applemail is QuotedPrintable
My c# code is:
                mail.BodyEncoding = System.Text.Encoding.UTF8;
                mail.BodyTransferEncoding = System.Net.Mime.TransferEncoding.EightBit ; (I've tried SevenBit+QuotedPrintable)
                SmtpServer.DeliveryFormat = SmtpDeliveryFormat.SevenBit;

Open in new window

I've tried a coupla others, but the content-transfer-encoding is always turning up as base64?
I can't believe I've just come across this and there's not much on the web about it.
Silas2Asked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

ste5anSenior DeveloperCommented:
I don't think it's an encoding problem. What does "raw html" mean? Have you considered the fact, that HTML e-mail bodies can only use a HTML subset and that different e-mail clients render this differently?

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Silas2Author Commented:
I mean the email app displays the words
<html><body> etc
, rather than rendering it.
When I look at the source (I mean the whole source including headers) the only difference I can spot between an email which renders ok in the apple app/thunderbird and my one is the encoding, the successful apple one is visible in plain text, my one is base64/garbled in view source, that's why I think its the encoding....it may not be.
ambienceCommented:
What content-type are you setting? Some API provide a method like setHtml() and internally adjust the content-type accordingly. Try the "text/html"  content type.
Silas2Author Commented:
This is so spooky, I've tried every combination...but I have to confess I have a .net mail at another website which is using the system.net defaults (i.e. setting no values for contenttype/transferencoding) and its working fine.
For some reason this one keeps sending utf8/base64 even if I force ascii to contenttype.
I've just seen this very old (2005) post about system.net.mail
https://social.msdn.microsoft.com/Forums/en-US/d9429eb3-f4b5-40ba-8e9e-b31702110d40/set-contenttypeencoding-in-systemnetmailmailmessage?forum=netfxnetcom

With System.Net.Mail we look at the body and kind of determine what the
best encoding to use. If your body has non ascii characters you should not
set the encoding as ASCII.
so maybe some dirt in the message is forcing the base64 encoding? (I can't see any...)
Silas2Author Commented:
Ah , you know what it is, AlternativeView, I was using one of those, that seems to force  base64.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Email Protocols

From novice to tech pro — start learning today.