standard authorization code flow failure

[machonky]

• I received the ClientId and Client Secret from developer.xero.com App configuration area with redirect URI: https://localhost:5001/Authorization/Callback.
• I've added the ClientId and Client Secret to the appsettings.json file.

When starting up with either the signup or sign-in options I get a javascript error:

TypeError: Cannot read properties of null (reading '1')
Stack trace:
 >  at H (https://edge.xero.com/style/xui-icon/6.8.3/iconLoader.js:2:109)
 >    at https://edge.xero.com/style/xui-icon/6.8.3/iconLoader.js:2:545
 >    at Array.forEach (<anonymous>)
 >    at l (https://edge.xero.com/style/xui-icon/6.8.3/iconLoader.js:2:476)
 >    at https://edge.xero.com/style/xui-icon/6.8.3/iconLoader.js:2:1031
 >    at https://edge.xero.com/style/xui-icon/6.8.3/iconLoader.js:1:121
 >    at https://edge.xero.com/style/xui-icon/6.8.3/iconLoader.js:1:125

I'm directed to an error page

Error: unauthorized_client
Invalid redirect_uri
Error code: 500