diff --git a/Gsm_SockInt_Open.c b/Gsm_SockInt_Open.c
index 5a18d0b..2c52930 100755
--- a/Gsm_SockInt_Open.c
+++ b/Gsm_SockInt_Open.c
@@ -122,7 +122,7 @@ uint8_t Gsm_Socket_open(tSocketGsm *env, eSocketType type, char *addr, size_t ad
 void Gsm_Socket_close(tSocketGsm *env, uint8_t contextId) {
 
     if (osMutexAcquire(env->access, defaultSocketTimeout) == osOK) {
-        if (contextId != SOCKET_WRONG_CONTEXT) {
+        if ((contextId != SOCKET_WRONG_CONTEXT) && (contextId != 0)) {
             AtGsmTelitLe910_CloseConnection(env->gsmAt, contextId);
             GsmSocketSlot_Clear(env->slots + contextId);
         } else {