Connect Origins to Destinations: Error

[JonathanBrooks6]

I am trying to connect 4,500 O's to 4,500 D's using Online. I have tried starting with CSV files and now Excel. I know I have the same number of points in each layer and that both layers have the same ID field. However, ArcGIS Online will not list any possible ID fields for either layer in the drop-down menu.

Must ID fields be a specific field type? I have tried string and double to no avail. Any guidance much appreciated.

[DanPatterson_Retired]

The field types must be the same type.

You should also move this to ArcGIS Online‌ since that is where you are trying to do it

[JonathanBrooks6]

The field types do match. I have tried matching the ID fields as both double and string. No success.

https://arcg.is/0rSaTj 

[FionaRenton1]

I found that I had to add an Integer field can calculate it to the ID for this to work.