Hi
I can share you my solution, although I think this should be part of the Newsletter configuration options.
– Goto you back-end of your host, most hosting providers offer a Control Panel
– Next use MYPHPADMIN or other tool to look at your WordPress database
– Select the table xxxx_newsletter_automated where xxxx is something specific for your website
– Now browse the table and find the row that is basically your newsletter, it holds the complete HTML
– Edit that record and find the code <body style=”margin: 0; padding: 0;”> and change it into <body bgcolor=”#cccccc”; style=”margin: 0; padding: 0;”>
– Where #cccccc is the hex code for your preferred color
Be aware the change will be gone if you change the newsletter in the ADMIN of your website using the Newsletter Plugin. So wait with the change until you’re happy with the Newsletter and will not make changes anymore.
Still, the plugin should support this out of the box.
Regards, Bart