I'll third (fourth?) the ask of what your subscription level is. My subscription is Marketing Hub Pro and Sales Hub Pro and I have no issues creating custom reports on a custom datetime object I have at the Contact level. I'd also ask what exact overall report you were doing - what was the visualization chart you wanted to use, what other properties did you have in the report, and did you have any filters set.
You could probably do this free with Demand Sage (shameless), but depending on your subscription level or access to the Reporting add-on we may be able to get it up in the HS dashboards with a bit more information.
Would love to be able to help, but I don't have access to report builder on my current subscription.
@sharonlicari - if HubSpot feels like upgrading me as a reward for being such an upstanding (?!) community member, I wouldn't complain!
Did my post help answer your query? Help the Community by marking it as a solution "The rest of my advice has no basis more reliable than my own meandering experience. I will dispense this experience... now!"
I second @AdamLPW on that one - I also don't currently have a Professional account to try this out (needed for Calculated fields). Would be great to have a full account with everything enabled for Community Champions to make such things quicker 😄
Sorry @MzSeJP , hope someone else can jump in here. Otherwise, might be worth reaching out to support if you haven't already to see if they can confirm whether that's a bug or just a limitation of the custom fields. It wouldn't totally surprise me if it is a limitation in which case the usual response of 'export it and report outside of HubSpot' applies - but that's not so helpful in this case, as you clearly want it for an operational dashboard.
Did I answer your question? If your question is answered, please mark it as a solution. If you need more help, hit that big orange 'Reply' button!