1) Welcome to the Party!
2) As you are obviously new here, I have some suggestions to help us all help you:
When you post, please post your entire configuration including (but not limited to) your installation method (7.X.X?) and vicidial version
with build (VERSION: 2.X-XXXx ... BUILD: #####-####).This IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "manual/from scratch" you must post your operating system with version (and the .iso version from which you installed your original operating system) plus a link to the installation instructions you used. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3) I'm not sure if the autodial script checks for auto-alt-dial statuses constantly or just when the script starts up, so you may want to give it a few minutes to see if it kicks in before jumping to any conclusions.
4) You did not specifically state that "B,N,NA,DC" or other statuses succeed in generating alt-number dials, although I'd like to read that into your statement I hate assumptions. So ... do they?
5) Please verify your calls are really in the campaign in which you added AB to the auto-alt-dial status list.
6) Is this a new issue or has this never worked before because you never had AB in the list for any other campaign in the past?
7) Please tell me you've dialed the other numbers a few times to be sure they are not just ALSO busy?