After setting up FAS, apps / desktops are failing to launch. 
On FAS servers we see event ID 101. 

Log Name: Application
Source: Citrix.Authentication.FederatedAuthenticationService
Date: Date and Time
Event ID: 101
Task Category: None
Level: Warning
Keywords: Classic
User: N/A
Computer:
Description: [S101] Server  is not authorized to assert identities in role [Default]. [correlation: 9] Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Citrix.Authentication.FederatedAuthenticationService" /> <EventID Qualifiers="0">101</EventID> <Level>3</Level> <Task>0</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2022-02-09T21:51:48.999735600Z" /> <EventRecordID>295</EventRecordID> <Channel>Application</Channel> <Computer></Computer> <Security /> </System> <EventData> <Data> is not authorized to assert identities in role [Default]. [correlation:]</Data> </EventData> </Event>

Check the rule on your FAS server, to ensure your STF is allowed in the "Manage StoreFront Permissions" page.
Be aware that by default, there is a DENY entry for Domain Computers. On windows DENY always "wins".
Can you check that the permissions from Storefront servers for groups such as domain computers is not set to Deny? 
> FAS rules > access control > domain computers > set to "Allow"
 

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Problem Cause

Deny was on for computer accounts

After setting up FAS, apps / desktops are failing to launch.  On FAS servers we see event ID 101.  Log Name: Application Source: Citrix.Authentication.FederatedAuthenticationService Date: Date and Time Event ID: 101 Task Category: None Level: Warning Keywords: Classic User: N/A Computer: Description: [S101] Server  is not authorized to assert identities in role [Default]. [correlation: 9] Event Xml: 101 3 0 0x80000000000000 295 Application is not authorized to assert identities in role [Default]. [correlation:]