diff --git a/src/backend/app/projects/project_crud.py b/src/backend/app/projects/project_crud.py
index e147b053f..637bae036 100644
--- a/src/backend/app/projects/project_crud.py
+++ b/src/backend/app/projects/project_crud.py
@@ -962,7 +962,7 @@ async def send_invitation_message(
 
     project_url = f"{settings.FMTM_DOMAIN}/project/{project.id}"
     if not project_url.startswith("http"):
-        project_url = f"http://{project_url}"
+        project_url = f"https://{project_url}"
 
     message_content = dedent(f"""
         You have been invited to join the project **{project.name}**.