You should probably open a support incident. They will walk you through changing the database password to a known hash value that you can then use to log on.
Here are the instructions since the link it broken to the wiki
Local Web Reports Admin: If access to Web Reports as a local admin user has been lost somehow:
Login to the BESReporting database in SQL
Determine if the username for the user you would like to create is already taken (for example: bigfix)
o select UserID from USER_NAMES where LoginName = 'bigfix’
o select UserID from USERS where LoginName = ‘bigfix’
If you want to delete this user ahead of recreating it, run the following delete queries:
o delete from USERS where UserID =
o delete from USER_NAMES where UserID =
o delete from ROLE_USER_ASSIGNMENTS where UserID =
Run the following query statement block to create the user (i.e. one named bigfix):
begin
declare @id int
insert into USER_NAMES ( LoginName, DisplayName, IsADUser ) values ( ‘bigfix’, ‘bigfix’, 0 )
set @id = (select UserID from user_names where LoginName = ‘bigfix’)
insert into USERS ( UserID, LoginName, PasswordHash, PasswordSalt ) values ( @id, ‘bigfix’, ‘gwCOEwCUD1ntCnCBwRDV+VzdvvM’, ‘1’ )
insert into ROLE_USER_ASSIGNMENTS ( UserID, RoleID ) values ( @id, 1 )
end
go
You should now be able to login to Web Reports using:
Username: bigfix
Password: bigfix