Please open your ApplicationLog located in ThingworxStorage/logs and inspect for errors. Something like the following might be observed:
**********LICENSING ERROR ANALYSIS
2017-03-31 16:29:19.591+0300 [L: ERROR] [O: ] [I: ] [U: SuperUser] [S: ] [T: localhost-startStop-1] C:\WINDOWS\Sun\Java\bin is listed as a java.library.path but it does not exist
2017-04-12 13:51:53.515+0200 [L: ERROR] [O: c.t.s.s.l.LicensingSubsystem] [I: ] [U: SuperUser] [S: ] [T: localhost-startStop-1] Failed to load FlxCore library. Ensure it's in PATH (Windows) or LD_LIBRARY_PATH(other platforms) or set with the VM arg, -Djava.library.path. Error message : com.flexnet.licensing.DllEntryPoint.entry([B)
Typically, if the license file has been downloaded and placed correcrtly, according to the 7.4 installation guide, the error in the log will specify where the file was found. If the license path was specified per the installation guide in the tomcat java path, you may try to clear it from the Tomcat java settings and keep these parameters:
And then set up the license path in the environment variable path:
Go to explorer, right click on "my computer" -> Properties -> Advanced settings -> Environment variables -> edit "PATH", add ; and then path to your tomcat extensions folder, “ ;<path to extensions folder of tomcat> “ or, for example ";C:\ptc\Thingworx\webapps\Thingworx\WEB-INF\extensions"