diff --git a/locales/en.json b/locales/en.json
index 667a8d4b3..faef3efc5 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -327,6 +327,7 @@
     "extracting": "Extracting...",
     "field_invalid": "Invalid field '{}'",
     "file_does_not_exist": "The file {path} does not exist.",
+    "file_extension_not_accepted": "Refusing file '{path}' because its extension is not among the accepted extensions: {accept}",
     "firewall_reload_failed": "Could not reload the firewall",
     "firewall_reloaded": "Firewall reloaded",
     "firewall_rules_cmd_failed": "Some firewall rule commands have failed. More info in log.",
diff --git a/src/yunohost/utils/config.py b/src/yunohost/utils/config.py
index cb493be03..23a95b565 100644
--- a/src/yunohost/utils/config.py
+++ b/src/yunohost/utils/config.py
@@ -797,7 +797,7 @@ class FileQuestion(Question):
             raise YunohostValidationError(
                 "app_argument_invalid",
                 field=self.name,
-                error=m18n.n("file_does_not_exists"),
+                error=m18n.n("file_does_not_exist", path=self.value),
             )
         if self.value in [None, ""] or not self.accept:
             return
@@ -807,7 +807,7 @@ class FileQuestion(Question):
             raise YunohostValidationError(
                 "app_argument_invalid",
                 field=self.name,
-                error=m18n.n("file_extension_not_accepted"),
+                error=m18n.n("file_extension_not_accepted", file=filename, accept=self.accept),
             )
 
 
@@ -833,7 +833,7 @@ class FileQuestion(Question):
             # i.e. os.path.join("/foo", "/etc/passwd") == "/etc/passwd"
             file_path = os.path.normpath(upload_dir + "/" + filename)
             if not file_path.startswith(upload_dir + "/"):
-                raise YunohostError("file_relative_parent_path_in_filename_forbidden")
+                raise YunohostError(f"Filename '{filename}' received from the API got a relative parent path, which is forbidden", raw_msg=True)
             i = 2
             while os.path.exists(file_path):
                 file_path = os.path.normpath(upload_dir + "/" + filename + (".%d" % i))