Issue:

When creating an online archive rule for collection archiving the following error is shown:

Invalid criteria field type field name: date, detected field type: string

Date format example: YYYY-MM-DDThh:mm:ss.ms

RCA:

This error gets thrown when the archive field that is supposed to be an ISODate field returns a String field instead.

Solution:

Check if the date field is polymorphic and potentially includes String values alongside Date values. The remediation here would be to convert those String values to Date.