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The LAS Supportability tool reported connectivity failure for the below LAS endpoints:
 
https://trust.citrixworkspacesapi.net:443
https://customers.citrixworkspacesapi.net:443
https://core.citrixworkspacesapi.net:443

The below ciphers were missing  and the ECDH key exchange was not enabled on the Delivery Controller.

•    ECDHE-ECDSA-CHACHA20-POLY1305
•    ECDHE-RSA-CHACHA20-POLY1305

Added the missing Ciphers on the Deliver Controller:
•    ECDHE-ECDSA-CHACHA20-POLY1305
•    ECDHE-RSA-CHACHA20-POLY1305

IIS Crypto : Use the IIS Crypto Tool: https://www.nartac.com/Products/IISCrypto

•    Run as admin 
•    Choose a template like “Best Practices” 
•    Apply → Reboot 
This automatically enables DHE and disables weak ciphers.

This article describes how to troubleshoot and fix the below issue:

After clicking migrate to LAS option in on-prem Studio, you may see the Activation Status as “NotActivated” and Activation Expiration may show “Expiration date invalid for this site”

Ensure the following pre-requisites are met:

1. TLS 1.2 or higher is enabled on DDC and License server.
2. ECDHE cipher suites present on both DDC and License Server listed in https://docs.citrix.com/en-us/licensing/current-release/license-server-getting-started.html#cipher-suite-order-and-requirements
3. No overly restrictive cipher policy blocking the ECDHE ciphers is enabled.