buildbot exception in on ofbiz-branch16

[buildbot]

The Buildbot has detected a build exception on builder ofbiz-branch16 while 
building . Full details are available at:
    https://ci.apache.org/builders/ofbiz-branch16/builds/15

Buildbot URL: https://ci.apache.org/

Buildslave for this Build: silvanus_ubuntu

Build Reason: The AnyBranchScheduler scheduler named 'on-ofbiz16-commit' 
triggered this build
Build Source Stamp: [branch ofbiz/branches/release16.11] 1787134
Blamelist: jleroux

BUILD FAILED: exception shell_1 upload_1

Sincerely,
 -The Buildbot