1) Welcome to the Party!
2) A few hints for forum beginners (primarily because you did not list the required vicidial build number or the installation method, so you must be new here!):
when you post, please post your entire configuration including (but not limited to) your installation method and vicidial version with 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 "from scratch" you must post your operating system and should also post the .iso version from which you installed your original operating system. 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) It is possible you have an overload situation (especially if you are on a virtual machine). But I've never heard of agents becoming closer instead of ready. On the other hand, you never mentioned if these were closers, so it could be simply that they are not allowed to receive the calls in queue or that many of these callers are listening to the "message" and cannot transfer to an agent until the message has completed. Many possibilities, requiring a more in-depth description. So: inbound or outbound calls? multiple ingroups? are the agents closers/fronters or just "READY" converted magically to "CLOSER" after terminating a call?
4) Best advice: Upgrade to the latest version of Vicidial (presently in 2.6 developer trunk and stable or 2.4 latest stable release). Vicibox.com is the recommended installer, but you can also upgrade "in place" via the SVN How To in the wiki at the top of this page.
5) Happy Hunting!