diff --git a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
index 19aa578..7527adf 100644
--- a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
+++ b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
@@ -697,7 +697,7 @@
 	if assigned_users:
 		from frappe.utils import get_fullname
 		assigned_users = ', '.join((get_fullname(user) for user in assigned_users))
-		message = _(f'First Response SLA Failed by {assigned_users}')
+		message = _('First Response SLA Failed by {}').format(assigned_users)
 		doc.add_comment(
 			comment_type='Assigned',
 			text=message