Bad Requests: How to Debug

Calling Octopus through TeamCity. Failing Octopus Deploy step, logs below. Any ideas on the next step to troubleshoot?
@@@
[15:52:27]Step 8/8: Octopus Deploy (Command Line) (5s)
[15:52:27][Step 8/8] Starting: B:\BuildAgent\temp\agentTmp\custom_script8454052143029988963.cmd
[15:52:27][Step 8/8] in directory: B:\BuildAgent\work\629d25ea571e9a54
[15:52:28][Step 8/8] Octopus Command Line Tool, version 1.0.0.0
[15:52:28][Step 8/8]
[15:52:28][Step 8/8] Finding project: Business Host
[15:52:28][Step 8/8] Handshaking with Octopus server: http://octopusdeploy.bvops.com/api
[15:52:30][Step 8/8] Handshake successful. Octopus version: 1.2.1.1447; API version: 2.0.0
[15:52:30][Step 8/8] Finding environments…
[15:52:30][Step 8/8] Finding steps for project…
[15:52:30][Step 8/8] Getting package versions for each step…
[15:52:31][Step 8/8] BusinessHost - latest: 1.4.3.55178
[15:52:33][Step 8/8] Creating release: 1.4.3.65073
[15:52:33][Step 8/8] POST http://octopusdeploy.bvops.com/api/projects/projects-99/releases?skip=0&take=20
[15:52:33][Step 8/8] Bad requests Bad Request
[15:52:33][Step 8/8] System.Exception: Bad requests Bad Request
[15:52:33][Step 8/8] at OctopusTools.Client.OctopusSession.ReadResponse(WebRequest request) in C:\src\ot2\Octopus-Tools\source\OctopusTools\Client\OctopusSession.cs:line 205
[15:52:33][Step 8/8] at OctopusTools.Client.OctopusSession.Create[TResource](String path, TResource resource) in C:\src\ot2\Octopus-Tools\source\OctopusTools\Client\OctopusSession.cs:line 86
[15:52:33][Step 8/8] at ProjectExtensions.CreateRelease(IOctopusSession session, Project project, List`1 latestVersions, String version, String releaseNotes) in C:\src\ot2\Octopus-Tools\source\OctopusTools\Extensions\ProjectExtensions.cs:line 64
[15:52:33][Step 8/8] at OctopusTools.Commands.CreateReleaseCommand.Execute() in C:\src\ot2\Octopus-Tools\source\OctopusTools\Commands\CreateReleaseCommand.cs:line 152
[15:52:33][Step 8/8] at OctopusTools.Infrastructure.CommandProcessor.Process(String[] args) in C:\src\ot2\Octopus-Tools\source\OctopusTools\Infrastructure\CommandProcessor.cs:line 43
[15:52:33][Step 8/8] Process exited with code 2
[15:52:33][Step 8/8] Step Octopus Deploy (Command Line) failed
@@@