Updating Custom Field with DateTime format value

I am having an issue with setting a custom field that has a DateTime value. I have found forum requests for this issue, but I have no been able to solve my issue when following previous responses from IFS engineers.

I have tried multiple dateTime formats and none of them have worked.

How would I be able to resolve this issue to be able to update my custom field correctly?

DateTimes should conform to ISO 8601 - Wikipedia, ex: ā€œ2000-01-13T01:01:01.001Zā€