1) Run the survey campaign without making any changes (just change a new campaign from 8368 to 8366). Test it. If it works as expected: Make ONE (count them: ONE) change and test again. If your change causes the campaign to fail, undo the last step to be sure that's the problem (as opposed to something "else" going wrong), then make your change again (correctly this time) and/or bring the problem here along with full details of what you expected, what happened, and settings you changed (from and to values).
2) You said "in given format" and yet you did not specify the format. I also suspect you have not since reopened that file in audacity (by downloading it from Vicidial's audio store to be certain it's the one you're actually using, not just one you "intended" to use) and verified the format.
3) Check the asterisk CLI to see what Asterisk has to say about this audio file. Is it missing? Is it not formatted? Is it playing but you're not hearing it? That's what the asterisk CLI is for. Troubleshooting!
Happy Hunting!