I have tried sending and HTML formatted email using ACYmailing for Joomla AND Mailchimp. It works for yahoo, msn, aim, my work domain but not for gmail.
I can send plain emails from my server to gmail but the HTML formatted newsletter doesn't work.
Someone suggested it may be my HTML code ~~~> Pastebin
I couldn't find a problem with it.
Just in case you're actually sending the HTML you reference in your question, note that it's invalid - you haven't wrapped it in the necessary <html> and <body> tags.
I realize it's likely you just forgot to include those tags in the pastebin reference, but just in case. Note that the w3c validator found several (minor) errors in the referenced fragment.
Some ideas:
Are you receiving a rejection or failed email response? If it is being rejected you should get an email explaining why which will be sent (although you will need to specify a correct from / reply-to email address to receive this).
The first thing I would check is if the IP you are sending from has been blacklisted by any spam services - most deliverability issues I have experienced have been due to this. You can check a fairly extensive list of spam blacklists (together with some additional email validation services) at MX Toolbox
If everything appears fine there it may be due to Gmail's fairly strict antispam criteria. To be accepted, an email should contain in the headers a valid email address for Return-Path. If this is not valid then there must be a Reply-To header with a valid email address.
Another important weapon in Googles antispam arsenal is SPF record checking - essentially a way of validating that an IP address is authorised to send email for a particular domain. This is worth checking however as far as I am aware a missing SPF record will only cause the mail to go into spam rather than not be delivered.
To kelbizzle..
Don't worry I had the exact same problem! I'm glad you asked the question as your solution worked! The email was ALWAYS going into the spam for some reason! Thanks guys :-)