https://userapps.support.sap.com/sap/support/knowledge/en/3740803
3740803 - Error "Do not enter a third-country supplier as LTSD issuer" in Fiori App ID F4419 | SAP...
in Manage Requests - LTSD app, when you input a supplier to LTSD Issuer it displays a Error, "Do not enter a third-country supplier as LTSD issuer"...