Symptoms
Error message “An error occurred trying to authenticate the user --> The server could not be contacted --> The LDAP server is unavailable” being displayed upon attempt to open any smartform or K2 Designer or K2 Workspace. No changes to K2 environments were made before this error appear. Error appears when accessing forms or K2 Designer both from client machines and from the K2 server.
Diagnoses
This error message is a bit misleading as it may be linked with LDAP connection strings and AD DS connectity. But it may also be related with issues with connectivity between K2 Server (one which hosts web applications, i.e. Workspace, Runtime and Designer) and SQL server.
For such symptoms it may be also necessary to check IIS authentication and LDAP connectivity. If those are seemingly in order you may run K2 Setup Manager in configuration mode and see if there are any errors reported during the process. In particular, in case of such symptoms you may see the following K2 database related error reported by K2 Setup Manager:
"The login is from an untrusted domain and cannot be used with Windows authentication."
"SQL user 'DOMAINUSERNAME' not updated in DATABASENAME database failed: Login failed. The login is from an untrusted domain and cannot be used with Windows authentication."
In such case you may also see similar messages logged in SQL server application logs and they indicate that K2 service account is unable to connect to SQL Server over the network from K2 server. In SQL server Application log this is being logged with event ID 17806 Logon errors, with the following details:
SSPI handshake failed with error code 0x8009030c, state 14 while establishing a connection with integrated security the connection has been closed. Reason: AcceptSecurityContext failed. The Windows error code indicates the cause of failure. iCLIENT: XXX.XXX.XXX.XXX]
Resolution
In case of SQL server related errors it may necessary to check whether K2 service account right “access this computer from the network” was revoked/denied on SQL server. RSOP (Resultant Set of Policies) could be run on SQL server to verify this. See related Microsoft documentation on this: Access this computer from the network
See also:
Common ‘SSPI handshake failed’ errors and troubleshooting
“SSPI handshake failed” could result when the security event log has reached the maximum log size
