Internal Server Error Trying to Migrate from OTRS 4

[labiculum]

Setting up Zammad worked fine but importing from OTRS via the web interface stalled. Trying again on the command line produces the errors described below. There are similar topics here and on Github, but none that really fit my case or help me solve that problem.

Infos:

• Used Zammad version: 2.4.0
• Used Zammad installation source: rpm (packager.io)
• Operating system: openSUSE Leap 42.3
• Browser + version: Firefox 52/57/59
• Migration source: OTRS 4

Expected behavior:

• Import from OTRS via command line completes successfully.

Actual behavior:

• After setting the import variables and starting the import from OTRS as per the Zammad documentation, HTTP 500 and runtime errors occur.

Steps to reproduce the behavior:

• standard installation of openSUSE (no GUI)
• install dependencies as per the Zammad documentation
• set up repositories for Elasticsearch and Zammad, install both
• run OTRS import via command line (see below)

Ruby console output:

USER@leap:~> sudo zammad run rails c
WARNING: Nokogiri was built against LibXML version 2.9.1, but has dynamically loaded 2.9.4
Loading production environment (Rails 5.1.4)
irb(main):001:0> Setting.set('import_otrs_endpoint', 'http://FQDN/otrs/public.pl?Action=ZammadMigrator')
Setting.reset_change_id: set new cache, 574177317
Setting.set('import_otrs_endpoint', "http://FQDN/otrs/public.pl?Action=ZammadMigrator")
=> true
irb(main):002:0> Setting.set('import_otrs_endpoint_key', 'KEY')
Setting.reset_change_id: set new cache, 676340037
Setting.set('import_otrs_endpoint_key', "KEY")
=> true
irb(main):003:0> Setting.set('import_mode', true)
Setting.reset_change_id: set new cache, 713646205
Setting.set('import_mode', true)
=> true
irb(main):004:0> Import::OTRS.start
thread#-: Start import...
thread#-: POST: http://FQDN/otrs/public.pl?Action=ZammadMigrator
thread#-: PARAMS: {:Action=>"ZammadMigrator", :Key=>"KEY"}
thread#-: loading SysConfig...
thread#-: POST: http://FQDN/otrs/public.pl?Action=ZammadMigrator
thread#-: PARAMS: {:Subaction=>"Export", :Object=>"SysConfig", :Limit=>"", :Offset=>"", :Diff=>0, :Action=>"ZammadMigrator", :Key=>"KEY"}
Setting.reset_change_id: set new cache, 904472499
Setting.set('http_type', "http")
Setting.reset_change_id: set new cache, 694726481
Setting.set('organization', "NAME")
Setting.reset_change_id: set new cache, 658119837
Setting.set('system_id', "01")
Setting.reset_change_id: set new cache, 240125243
Setting.set('ticket_hook', "Ticket#")
Setting.reset_change_id: set new cache, 869131259
Setting.set('ticket_number', "Ticket::Number::Date")
Setting.reset_change_id: set new cache, 170644133
Setting.set('ticket_number_date', {:checksum=>true})
thread#-: loading DynamicField...
thread#-: POST: http://FQDN/otrs/public.pl?Action=ZammadMigrator
thread#-: PARAMS: {:Subaction=>"Export", :Object=>"DynamicField", :Limit=>"", :Offset=>"", :Diff=>0, :Action=>"ZammadMigrator", :Key=>"KEY"}
thread#-: ERROR: Server Error: #<Net::HTTPInternalServerError 500 Internal Server Error readbody=true>!
thread#-: POST: http://FQDN/otrs/public.pl?Action=ZammadMigrator
thread#-: PARAMS: {:Subaction=>"Export", :Object=>"DynamicField", :Limit=>"", :Offset=>"", :Diff=>0, :Action=>"ZammadMigrator", :Key=>"KEY"}
thread#-: ERROR: Server Error: #<Net::HTTPInternalServerError 500 Internal Server Error readbody=true>!
thread#-: POST: http://FQDN/otrs/public.pl?Action=ZammadMigrator
thread#-: PARAMS: {:Subaction=>"Export", :Object=>"DynamicField", :Limit=>"", :Offset=>"", :Diff=>0, :Action=>"ZammadMigrator", :Key=>"KEY"}
thread#-: ERROR: Server Error: #<Net::HTTPInternalServerError 500 Internal Server Error readbody=true>!
RuntimeError: Zammad Migrator returned an error
        from lib/import/otrs/requester.rb:129:in `post'
        from lib/import/otrs/requester.rb:90:in `request_json'
        from lib/import/otrs/requester.rb:77:in `request_result'
        from lib/import/otrs/requester.rb:34:in `load'
        from lib/import/otrs.rb:142:in `import_action'
        from lib/import/otrs.rb:73:in `import'
        from lib/import/otrs.rb:157:in `base_objects'
        from lib/import/otrs.rb:41:in `start'
        from (irb):4
irb(main):005:0>