We are currently investigating reports of Electrum Firo not working with the new Ledger app for Firo and we are in touch with Ledger.
If you need to access Electrum Firo, please remain on Firo app version 2.2.0 for now.
EDIT: This problem was fixed in Firo app version 2.4.5.
EDIT 2: We have released 4.1.5.4 which should fix any additional issues.