UserID/Password Invalid Siebel 8.0

An issue was reported with logging to dedicated client on Siebel 8.0. The reported behavior is error we had to face while connecting to Dedicated Client in Siebel 8.0version
User cannot access database using dedicated web client with following message
"User ID or Password is invalid".
Although we can connect to the database through dbisqlc.exe

Using the same userID or password you can connect to database.

To fix this issues, try the following things
1. Navigate to Siebel 8.0\webclient\bin and rename the diccache.dat file if file exists.
2. Delete all the files *.spf.
3. Try changing the SRf who are using to connect to dedicated client.