Knox County high school seniors -- and seniors across the state -- won't be able to take the ACT test on Oct. 2 as originally planned because of a suspected security compromise.

The date has been canceled, with Tennessee Education Commissioner Candice McQueen forwarding an email statewide from ACT's Chief Operating Officer Janet Godwin to districts that said the nonprofit was scrubbing the Oct. 2 test date "to ensure the exam is fair and valid," the Tennessean reported.

The group found "credible evidence that there was a compromise in the testing process related to the October 2 test date."

Knox County Schools tweeted Friday morning that the Oct. 2 would no longer be available. According to Knox County Schools, this is the one-time free ACT test that students from Tennessee are given.

Since the Oct. 2 test date has been canceled, the test is being offered on Oct. 16 and Oct. 30, which are also school days. Each school will make its own decision about which day the free ACT will be offered, according to KCS spokesperson Carly Harrington.

It's unclear how many Knox County students were affected by this.

Tennessee requires students to take and pass the ACT in order to graduate high school.

Several test windows were to be available this fall. It's unclear how many Tennessee districts are affected by the Oct. 2 test date cancellation.

"We deeply regret that you are affected by this unfortunate situation and sincerely apologize for any inconvenience it may cause you, your staff, and students," Godwin's email says.

Any tests administered prior to Oct. 16 will not be scored, according to Godwin's email.

"For districts that cannot participate in either day, ACT will make vouchers available to enable students to test on December 8 at an available Saturday test center," Godwin's email says.

McQueen, in the forwarded email, asked districts to reach out to ACT for any further guidance on the test date's cancellation or the administration of the test.