# Setup: License key is invalid error message

**URL:** <https://discuss.workflowgen.com/t/setup-license-key-is-invalid-error-message/114>\
**Category:** Installation\
**Created:** [July 21, 2013, 2:20am UTC](https://discuss.workflowgen.com/t/setup-license-key-is-invalid-error-message/114 "2013-07-21T02:20:04Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![wfg-admin](https://yyz2.discourse-cdn.com/flex030/user_avatar/discuss.workflowgen.com/wfg-admin/32/714_2.png) [@wfg-admin](https://discuss.workflowgen.com/u/wfg-admin)\
**Post date:** [July 21, 2013, 2:20am UTC](https://discuss.workflowgen.com/t/setup-license-key-is-invalid-error-message/114/1 "2013-07-21T02:20:04Z")

</div>

**Issue**

You keep getting the `License key is invalid` error even after copying both the license key file and serial number, and you reset IIS as a workaround, after which WorkflowGen works properly.

**Solution**

You have to remove the server cache. To do this:

1. Stop IIS.

2. Delete all files in `C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files`.

3. Restart IIS.