When admin browses to Targeting tab, sees error "Invalid URI: Value cannot be null. Parameter name: input" in messaging center

Question

When admin browses to Targeting tab, sees below error in messaging center.
"Invalid URI: Value cannot be null. Parameter name: input"

With Fiddler running in the background, see that issue may be related to below call. On a working 8.5 test server, below URL results in a header which has param InstanceId, and value CdEnvironmentStagingId. On offending server, same call gives a 500 error and has the TCM id of the publishing target configured in the Targeting tab of the target. Wondering if the problem is due to param InstanceId incorrectly being used for server configured to use the legacy publishing framework, and how this might be changed to use param PublicationTargetId instead.
Working Server Web 8.5 - 200
http://localhost/WebUI/Models/SmartTarget/Services.svc/GetPromotions {"filter":{"InstanceId":"CdEnvironmentStagingId","implementingInterface":"Tridion.ContentManager.ListFilter"}}
Working Server Tridion 2013 SP1 HR1, ST 2014 SP1 - 200 http://localhost/WebUI/Models/SmartTarget/Services.svc/GetPromotions
{"filter":{"PublicationTargetId":"tcm:0-9-65537","implementingInterface":"Tridion.ContentManager.ListFilter"}}
Offending Server Web 8.1 - 500
http://localhost/WebUI/Models/SmartTarget/Services.svc/GetPromotions {"filter":{"InstanceId":"tcm:0-170-65537","implementingInterface":"Tridion.ContentManager.ListFilter"}}

Details

• Web 8.1.1
• Experience Optimization 8 (Fredhopper 7.5.2)
• Using legacy publishing framework
• Several promotions had previously been created successfully, but at some point the issue began to happen with no known configuration change.
• The EO management service URL can be browsed to successfully, as can the Promotions web service call.
  http://localhost:8093/management.svc
  http://localhost:8093/management.svc/Promotions
• No errors seen in Management service core logs with debug enabled.
• For troubleshooting purposes, have made visible promotions in the Fredhopper Business Manager.
• Have compared and validated the Management service config files for offending server against the Web 8.5 working server, including smarttarget_conf.xml.
• No log entries related to error seen in Windows event logs for Tridion or Application category.
• No relevant info seen when tracing CM using PS scriptlet Start-TcmTracing.

Suggestions welcome, thanks.

Answer 1

Issue was due to a campaign directly being created in the Fredhopper Business Manager (FBM), and labeled SmartTarget (ST). Issue no longer reproducible when the label is removed from campaign.

Just as recap, even though for troubleshooting purposes it is possible to make SDL Web promotions visible in the FBM, and the default FH admin user is able to create campaigns directly in that dashboard, ST data should always be created from the Targeting tab of CME. The FH admin user is able to create data because aside from ST integration purposes, FH is used as a standalone product.