Citrix Licensing Manager Reports Error Code 400

After upgrading licence server to 11.15.0.0 build 25000, Citrix Licensing Manager https://localhost:8083 displays the error :For assistance, contact Citrix Customer Service and reference error code 400...

Error: Citrix Licensing Manager could not complete the operation. If you are trying to allocate a license, go to My Account.

The error "Citrix Licensing Manager could not complete the operation. If you are trying to allocate a license, go toMy Account. For assistance, contact Citrix Customer Care" is returned after allocating a license using Citrix Licensing Manger...