Advanced Predictions error: ML data pre-processing failed Unable to load the following resource

Summary:

Just like the title says.. I get the following obscure error. Does anyone have any suggestions?

ML data pre-processing failed
Unable to load the following resource: A service error has occurred. Select 'Provide Feedback' and contact Oracle Support. Reference: a5520ede-3aa5-4a2d-b8e9-b16cedf757bd

I've verified the obvious:

• Verified driver data exists. (turned
• double checked my calendar setup
• Tried running with featuring with engineering features turned on and off
• tried with confidence intervals turned on and off
• there are no events turned on
• Predict missing input driver values is on (I don't have forecasted drivers)