Error: Exception Caused in validateClassifier method

If you are receiving this error, please continue reading below.:

Some User-Defined Fields (such as those on the RFI Detail tab) have look-up values assigned to them that you can select from by clicking on the magnifying glass icon in the field. See screenshot below. This is the recommended approach.

It is recommended that you click the magnifying glass and select one of the available look-up values (or "Add New" in the look-up window), rather than:

1) Manually typing your entry directly into the field. Especially if it doesn't match an LOV option. See screenshot below.

2) Selecting an auto-fill option suggested by your browser. Especially if it does not match an option in the LOV. See screenshot below. 

Manually typing or selecting a auto-fill option will likely result in the error pictured at the beginning of this article.