Package works from VS and SSMS. Fails when run by DTExec.exe

I have an SSIS package, Lesson5.dtsx, deployed to SSISDB in project deployment mode. When I Right-Click on it in SSMS and choose "Execute..." it is successful. When I try to run from DTExec.exe it fails with the following message. What might be the problem?

C:>dtexec /Server localhost /envreference "Lesson5-devl" /isserver "\SSISDB\SSISTutorial\SSISTutorialDeployment\Lesson5.dtsx"
Microsoft (R) SQL Server Execute Package Utility
Version 14.0.3026.27 for 32-bit
Copyright (C) 2017 Microsoft. All rights reserved.

Started:  16:40:58
Failed to execute IS server package because of error 0x80131537. Server: localhost, Package path: \SSISDB\SSISTutorial\SSISTutorialDeployment\Lesson5.dtsx, Environment reference Id: Lesson5-devl.
Description: Input string was not in a correct format.
Source: mscorlib
Started:  16:40:58
Finished: 16:40:58
Elapsed:  0.094 seconds