diff --git a/Koha/REST/V1/Patrons.pm b/Koha/REST/V1/Patrons.pm
index 8cc0e0b3e4..b6d009c643 100644
--- a/Koha/REST/V1/Patrons.pm
+++ b/Koha/REST/V1/Patrons.pm
@@ -183,9 +183,12 @@ sub add {
                     openapi => { error => "Given " . $to_api_mapping->{ $_->broken_fk } . " does not exist" }
                 );
             } elsif ( $_->isa('Koha::Exceptions::BadParameter') ) {
+                my $parameter = $to_api_mapping->{ $_->parameter } || $_->parameter;
+                my $error =
+                    $parameter ? "Given " . $to_api_mapping->{ $_->parameter } . " does not exist" : $_->full_message;
                 return $c->render(
                     status  => 400,
-                    openapi => { error => "Given " . $to_api_mapping->{ $_->parameter } . " does not exist" }
+                    openapi => { error => $error }
                 );
             } elsif ( $_->isa('Koha::Exceptions::Patron::MissingMandatoryExtendedAttribute') ) {
                 return $c->render(