diff --git a/src/at.c b/src/at.c
index 399913c..2527bca 100644
--- a/src/at.c
+++ b/src/at.c
@@ -68,8 +68,14 @@ gboolean at_send_command(struct EG25Manager *manager)
         else if (at_cmd->subcmd && at_cmd->value)
             len = snprintf(command, sizeof(command), "AT+%s=\"%s\",%s\r\n", at_cmd->cmd, at_cmd->subcmd, at_cmd->value);
 
-        if (len < 0 || len >= sizeof(command)) {
-            g_warning("AT command does not fit into buffer\n");
+        if (len < 0) {
+            g_warning("snprintf(3) failed");
+            at_next_command(manager);
+            return FALSE;
+        }
+        else if (len >= sizeof(command)) {
+            g_warning("AT command does not fit into buffer "
+                "(%d bytes required, %zu available)", len, sizeof(command));
             at_next_command(manager);
             return FALSE;
         }