I am using version 1.1.3 of the plugin.
Our AD system requires @ourdomain.com to be appended to logins to work. This makes the full login is email@example.com. When I set up the "Account suffix" option to be @ourdomain.com it never adds it. When I log in with my name the test window says "[NOTICE] trying account suffix """, even though I have @ourdomain.com set in the account suffix area. Under the adLDAP options it says "account_suffix: ", so it seems the account suffix I am setting is never getting used. I have tried adding a ';' just in case and it doesn't help.
When I leave account suffix blank and I log in with firstname.lastname@example.org it works perfectly fine. It logs me in, creates the account, etc.