Our senior dev left us recently and i'm trying to swim into the ocean that is IdentityServer.

There is a few things I don't understand and can't find informations on it.
Like for example, when you run the client application, it is redirrected to `IdentityServer/Account/Login` with a parameter called `returnUrl`.

That `returnUrl` seems to be used for many things, like retrieving the authorization context with :

```
await _interaction.GetAuthorizationContextAsync(returnUrl);

```

**My first question would be :** 

From where is that returnUrl coming from? how/where is it created?

**Second question is :** 

Is there a way to store it somewhere in the client application after you sign-in?
I mean, there is a point in the client application where we have to send mails to create new accounts. 
Those mails redirrect new users in a "register" page in IdentityServer. 
What i'd like to do is to have the returnUrl here to redirrect the new user to the correct client application.

Thanks for your time !

**EDIT :**

here is the return url set in my Client (in IdentityServer) :

```
RedirectUris = {"http://localhost:44349" + "/signin-oidc"}

```

and here is the returnUrl recieve by the Login method in IdentityServer when i start the client application 

```
"/connect/authorize/callback?client_id=MyApplication_Web&redirect_uri=http%3A%2F%2Flocalhost%3A44349%2Fsignin-oidc&response_type=code%20id_token&scope=openid%20offline_access%20roles%20Cri_Identity_Serveur_Api.Full_Access&response_mode=form_post&nonce=637230882720491348.YmQzODA4ZTQtNDczZS00OWYwLWFmNmEtYjA2NmQ3YmIwZjg2YzdiODk4ZDYtMTU1YS00ZTM0LWE0MGEtNDVjOWNkZWFiYTM1&state=CfDJ8Ly2XCz96vdGkR4YQuJ4jeE-v9P4l1W7fLWpJcCGZpt1rMpXyWqEGdnaeRZfiZy4M4Z79LcixUbo06zImhsxwbgyV4hK82qmn0mI6wkrxwraT1tH3XNCdSXCfUJqwk_hZguMSwspZDEN6r1WxnZsU9kT8MHrb9qpzsMOMzsotVzToEjgMtxIeoRfqFSoK8ZfUXBkSw__qxVyIe1lCs96-I--ufZSyO2pBe2kfau-ah7eR5-9oopxX6x1k0tzFHAk6Y3_jMqGysES_GmmfeUJvXXFIR35Rc-IaxU1igswmL2h1IUS-0DQ98Tv_Gf3hirnS87SU87aSJhajgn2YmARXWc&x-client-SKU=ID_NETSTANDARD2_0&x-client-ver=5.3.0.0"

```

it seems that to retrieve the autorization context using `await _interaction.GetAuthorizationContextAsync(returnUrl);` the returnUrl must be the entire url with `"/connect/authorize/callback?..."`