The only thing I can think of is that the SSL certificate was generated for the website without www, I've renewed the certficate which might help.
You'll have to reupload the missing template, go onto your website and deactivate it. Unfortunately that's the only way to fix this in v1.
Have you tried resetting the banner and selecting it again?
As long as you have force SSL and a valid SSL certificate it should say secure; can you send me a link to your website?
Currently you need to click "Copy" in the StaffCP -> Layout -> Templates tab to copy an existing template and edit the files. If you want to add a premium template that you have purchased, please open a ticket in the Nameless Hosting dashboard.
Version 2.0.0 pre-release 7 has been released!
New features in this update include a new Italian translation, support for custom plural forms in translations, per-user templates and many fixes. A full changelog can be found here.
New installations can find the release here, and existing v2 installations can upgrade in the StaffCP -> Update tab.