The U.S. Financial Industry Regulatory Authority (FINRA) announced on Wednesday that 208 test takers were impacted by a “configuration error” that resulted in them incorrectly receiving a failing grade in the Series 24 supervisory exam.

The exam tests knowledge of critical functions, rules and statutory regulations necessary to supervise the management of a general securities broker-dealer firm.

The error arose in a new version of the exam, which was introduced on July 13, FINRA said in a statement.

FINRA staff noticed an unusual increase in test failures during a routine review of the results, the regulatory says. They then identified the issue, corrected it, and carried out a review to ensure that no other exam series was affected.

Approximately 1,421 people took the exam between July 13 and Sept. 24, when the error occurred. FINRA says it is notifying all of the affected firms and is correcting individual records in its database.

The error only caused incorrect failing grades, FINRA says, no one improperly received a passing grade.