# SSO client link giving error 500

**URL:** https://meta.discourse.org/t/sso-client-link-giving-error-500/86854
**Category:** WordPress
**Created:** [May 5, 2018, 11:03pm UTC](https://meta.discourse.org/t/sso-client-link-giving-error-500/86854 "2018-05-05T23:03:43Z")
**Posts on this page:** 1
**Showing post:** 6

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### Author: ![nylen](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/nylen/32/125684_2.png) [@nylen](https://meta.discourse.org/u/nylen)
#### Post date: [July 23, 2019, 7:12am UTC](https://meta.discourse.org/t/sso-client-link-giving-error-500/86854/6 "2019-07-23T07:12:38Z")

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For anyone else experiencing this error, I fixed it by filling in the `sso provider secrets` setting for the client domain name:

 ![00](https://global.discourse-cdn.com/meta/original/3X/6/5/65f1385843255589d104c0ea02567a589ac1ead6.png)

In the Discourse code, when this secret is not set, the call to `OpenSSL::HMAC.hexdigest` fails with the following error in the logs:

> TypeError (no implicit conversion of nil into String) /var/www/discourse/lib/single\_sign\_on.rb:114:in `hexdigest’

Here is the relevant code path:

- [discourse/lib/single\_sign\_on\_provider.rb at f364317625ee273d1e8983faa271831db912953b · discourse/discourse · GitHub](https://github.com/discourse/discourse/blob/f3643176/lib/single_sign_on_provider.rb#L21-L34)
- [discourse/lib/single\_sign\_on.rb at f364317625ee273d1e8983faa271831db912953b · discourse/discourse · GitHub](https://github.com/discourse/discourse/blob/f3643176/lib/single_sign_on.rb#L69)
- [discourse/lib/single\_sign\_on.rb at f364317625ee273d1e8983faa271831db912953b · discourse/discourse · GitHub](https://github.com/discourse/discourse/blob/f3643176/lib/single_sign_on.rb#L112)

This error message should definitely be improved! \_Edit: and it has been - see [https://meta.discourse.org/t/confusing-unpolished-error-message-when-using-discourse-as-sso-provider/123762\_](https://meta.discourse.org/t/confusing-unpolished-error-message-when-using-discourse-as-sso-provider/123762_)

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