As Suman mentioned this could be an issue with LDAP at first place. There could be other possible areas you might need to check along with LDAP
1. if you/ your organization using Clarity via On-Demand Model and If LDAP is enabled then you certainly check with CA.
2.If 1st point is not true - please see my comments.
2.1 Have you/your organization made any changes to your Clarity usernames recently? if yes - please do remember BO User information is different from Clarity User information. Try logging in using old BO information.
2.2 If 2.1 case is not true - is this issue happening with all of your Development team members? if not please try to log in with other team members credentials to access and reset your BO Password and then try logging in again.
2.3 Have you tried to login using Admin Account of BO?
3.Last thing you may need to check - Are you able to run the reports from Clarity? If not apparently this issue is happening because of your "Create Business Objects Users" might not be In - Sync with your BO Server. Please check this schedule / logs for this Job
Hope my inputs helps, let me know how it goes.