Hello Lucas,
Would you please check this procedure:
1. Log in to DeviceManager.
2. Choose Services > Block Service > Host > CHAP Authentication.
3. Select the CHAP authentication you want to modify, click
, and select Modify.
The Modify CHAP Authentication page is displayed.

4. Enter the new password for the CHAP authentication.
5. Click OK.
6. Confirm your operation as prompted.
Thanks.