Issue #11 - thanks @BKWJYK

Author: livialima

docs/21.md

@@ -45,7 +45,7 @@ Even if you don’t want/need certs, the outline of the topics in these referenc
 
 * [LinkedIn Learning](https://www.linkedin.com/learning/search?keywords=linux)
 * [Udemy](https://www.udemy.com/topic/linux/)
-* [CBT Nuggets](https://www.cbtnuggets.com/it-training/linux-found-cert-sys-admin)
+* [CBT Nuggets](https://www.cbtnuggets.com/it-training/linux/certified-system-administrator)
 
 
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