If the password of the DevTest built-in user id admin is lost, there is no way to recover it, but you can reset it.
Is there a way to recover the DevTest password for built-in user id admin as opposed to changing it?
All supported DevTest releases and platforms.
We cannot recover it, only reset it to its original value.
Execute DEVTEST_HOME\bin\resetadminuser.bat on Windows.
Execute DEVTEST_HOME/bin/resetadminuser.sh on Linux.
This will reset to the original value of admin.
You can change value of the admin account on the Server Console in Administration in DevTest versions 9.1.0 and earlier.
But you need to be a Super User to change it.
For DevTest versions 9.5.1 and later, it is changed on the Portal in Settings.
Knowledge document: TEC1745116
If you still are getting issues even after doing a reset saying "Bad credentials", your database is probably not UTF-8.