The login packet used to open the connection is structurally invalid; the connection has been closed. Please contact the vendor of the client library

Change the MaxTokenSize on the server computer

Error: 

The login packet used to open the connection is structurally invalid; the connection has been closed. Please contact the vendor of the client library

If you face error,  this could be due to "MaxTokenSize ".

To change the MaxTokenSize on the server computer

1. On the Start menu, click Run.
2. Type regedit, and then click OK. (If the User Account Control dialog box appears, click Continue.)
3. Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\Kerberos\Parameters.
4. If the MaxTokenSize parameter is not present, right-click Parameters, point to New, and then click DWORD (32-bit) Value. Name the registry entry MaxTokenSize.
5. Right-click MaxTokenSize, and then click Modify.
6. In the Value data box type the desired MaxTokenSize value. I put 20,000 Decimal

Note:

Hexadecimal value ffff (decimal value 65535) is the maximum recommended token size. Providing this value would probably solve the problem, but could have negative computer-wide effects with regard to performance. We recommend that you establish the minimum MaxTokenSize value that allows for the largest token of any user in your organization and enter that value.

7. Click OK.
8. Close Registry Editor.
9. Restart the computer.

Reference Link: http://sequelserver.blogspot.com/2013/07/error-17832-login-packet-used-to-open.html