Fixed JWT Specification Link (SharePoint#2060)

Author: thechriskent

docs/sp-add-ins/handle-security-tokens-in-provider-hosted-low-trust-sharepoint-add-ins.md

@@ -376,7 +376,7 @@ The logic in your application must get the authorization code from the query par
 
 ## JWT time values
 
-The `nbf` and `exp` claims are in the format specified by the [JWT specification](http://self-issued.info/docs/draft-goland-json-web-token-00l). They are written as the number of seconds since January 1, 1970. In C#, you can translate these values with the following code, where `jWTTimeStamp` is the value from the token, such as `1335822895`.
+The `nbf` and `exp` claims are in the format specified by the [JWT specification](https://tools.ietf.org/html/rfc7519). They are written as the number of seconds since January 1, 1970. In C#, you can translate these values with the following code, where `jWTTimeStamp` is the value from the token, such as `1335822895`.
 
 ```csharp
 DateTime exp = new DateTime(1970,1,1).AddSeconds(jWTTimeStamp);
@@ -394,4 +394,4 @@ The free [Fiddler tool](http://www.telerik.com/fiddler) can be used to capture t
 - [SharePoint code sample: Hello World remote add-in using CSOM](https://code.msdn.microsoft.com/SharePoint-2013-Hello-0fd15fbf)
 - [SharePoint Add-ins sample pack](https://code.msdn.microsoft.com/office/Apps-for-SharePoint-sample-64c80184)
 - [Creating SharePoint Add-ins that use low-trust authorization](creating-sharepoint-add-ins-that-use-low-trust-authorization.md)
-- [Authorization and authentication of SharePoint Add-ins](authorization-and-authentication-of-sharepoint-add-ins.md)
+- [Authorization and authentication of SharePoint Add-ins](authorization-and-authentication-of-sharepoint-add-ins.md)