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 (11.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 (EG: vSphere Version 6.X.X). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox 11.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 Mbd | Core2Quad Q6600 CPUs
3) Have you activated enhanced disconnect logging in System Settings? This setting may differentiate those two from each other.
4) Can you confirm that your "Cancel" is when the system times out and Vicidial terminates the call due to a timeout (25 seconds from your example) whereas "Congestion" is a call rejection by asterisk (cusomarily due to the carrier returning an error code of some sort)? If so, you could also use a dialplan line to differentiate these two and set the status based on the call attempt result instead (overkill, of course, but will work so I figured I'd mention it). This is actually what the enhanced disconnct logging is meant to avoid, or at least one of the things.
5) Of course if you change your dial timeout to 45 seconds, you'll get fewer cancels and more real results. Many telcos don't return a rejection before 25 seconds. They actually may all be disconnected numbers.
Happy Hunting!