If you have exchange 2013 which uses NTLM authentication and you can't sleep, because every time than you start Outlook you must enter a password....
Solution:
Edit group policy Lan Manager Authetification level, set it to Send NTLM responses only or above.
or
You must set the LmCompatibilityLevel on your client to a value of 2 or 3. To do this, follow these steps.
1. Click Start, click Run, type regedit in the Open box, and then press ENTER.
2. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\
3. In the right pane, double-click lmcompatibilitylevel.
4. In the Value data box, type a value of 2 or 3 that is appropriate for your environment, and then click OK.
5. Quit Registry Editor.
6. Restart your computer.
Solution:
Edit group policy Lan Manager Authetification level, set it to Send NTLM responses only or above.
or
You must set the LmCompatibilityLevel on your client to a value of 2 or 3. To do this, follow these steps.
1. Click Start, click Run, type regedit in the Open box, and then press ENTER.
2. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\
3. In the right pane, double-click lmcompatibilitylevel.
4. In the Value data box, type a value of 2 or 3 that is appropriate for your environment, and then click OK.
5. Quit Registry Editor.
6. Restart your computer.
