Symptoms

K2 Smartforms Designer occasionally returns license errors
 

Diagnoses

The K2 Smartforms Designer site sometimes displays an error stating: "The server is not licensed (MachineName: CHADWOSDWEB1, MachineCode: 04E38E291DF5BE6C).". The K2 Blackpearl Service itself is still accessible through the K2 Studio, and the K2 Workspace site still functions. Checking the license information shown in the K2 Workspace for the server in question shows the licenses as valid.

Executing an IISReset on the website hosting the K2 Designer resolves the issue. The issue has appeared in two separate environments.

I've attached a log from the K2 Blackpearl server from when the licenses failed to validate--it's at line 1455 in the file (on 2015-10-22 08:01:48 if you believe the timestamps, which you probably shouldn't).
 

Resolution

Issue:
Occasional license errors appear in Designer

Symptoms:
Log shows
"674503","2015-10-22 08:01:48","Warning","System","1045","InvalidLicense","SourceCode.Hosting.Server.Runtime.HostLicenseManager.ValidateLicense","1045 License Key ***************is invalid.","system","::1",":D:AppsK2 blackpearlHost ServerBin","628102","************************",""
"674504","2015-10-22 08:01:48","Warning","System","1045","InvalidLicense","SourceCode.Hosting.Server.Runtime.HostLicenseManager.ValidateLicense","1045 License Key **************is invalid.","system","::1",":D:AppsK2 blackpearlHost ServerBin","628102","************************",""

Resolution:
License key type mismatch. Requested and applied new keys, then restarted Blackpearl service.