Error 401 Unauthorized. How to Use the same token for different Urls?

Question

In ASP.Net Identity using Oauth2 a token is created once the user is authenticated posting User and Password.

Before making a call to an action from one API, the use

Answer 1

Finally I found the solution adding the same machineKey tag in both Web.config files:

<system.web>
...
<machineKey validationKey="57B449BBA8F9E656087FF7848727E122C5F5966F65AC0FC25FB3532193B59CFCD13B370883FFC184C1F1500638F33E6F67B37CAED1D9BC65BBC6CFFB232BFD0B" decryptionKey="6D9FBE88D16B3FA5B5E6B37460BBE50DA85D5B4C482159006B5A337C58AA9E79" validation="SHA1" decryption="AES" />
...
</system.web>

as is suggested on the accepted answer here using a machineKey generator.

From the documentation:

Sharing Authentication Tickets Across Applications
If you need a single logon to work across multiple applications located in separate virtual directories, you need to share a common authentication ticket. To configure a common authentication ticket, you must manually generate validationKey and decryptionKey values and ensure that each application shares these values. If you want to share tickets across all applications on your server you can set these manual values on the element in the machine level Web.config file. To share tickets across specific applications, you can use a element with common validationKey and decryptionKey values in the relevant application's Web.config files.

Updated - Security Warning

Security warning

There are many web sites that will generate a element for you with the click of a button. Never use a element that you obtained from one of these sites. It is impossible to know whether these keys were created securely or if they are being recorded to a secret database. You should only ever use configuration elements that you created yourself.

Read the Appendix A on the link to know how to generate your own machineKey element.