diff --git a/src/modules/cnxcc/cnxcc_mod.c b/src/modules/cnxcc/cnxcc_mod.c
index 55d9bf00a13..82bcb9e0168 100644
--- a/src/modules/cnxcc/cnxcc_mod.c
+++ b/src/modules/cnxcc/cnxcc_mod.c
@@ -1578,6 +1578,7 @@ static int ki_set_max_credit(sip_msg_t *msg, str *sclient, str *scredit,
 {
 	credit_data_t *credit_data = NULL;
 	call_t *call = NULL;
+	hash_tables_t *hts = NULL;
 
 	double credit = 0, connect_cost = 0, cost_per_second = 0;
 
@@ -1619,6 +1620,12 @@ static int ki_set_max_credit(sip_msg_t *msg, str *sclient, str *scredit,
 		return -1;
 	}
 
+	if(try_get_call_entry(&msg->callid->body, &call, &hts) == 0) {
+		LM_ERR("call-id[%.*s] already present\n",
+		msg->callid->body.len, msg->callid->body.s);
+		return -4;
+	}
+
 	LM_DBG("Setting up new call for client [%.*s], max-credit[%f], "
 		   "connect-cost[%f], cost-per-sec[%f], initial-pulse [%d], "
 		   "final-pulse [%d], call-id[%.*s]\n",
@@ -1796,6 +1803,7 @@ static int ki_set_max_channels(sip_msg_t *msg, str *sclient, int max_chan)
 {
 	credit_data_t *credit_data = NULL;
 	call_t *call = NULL;
+	hash_tables_t *hts = NULL;
 
 	if(parse_headers(msg, HDR_CALLID_F, 0) != 0) {
 		LM_ERR("Error parsing Call-ID");
@@ -1826,6 +1834,12 @@ static int ki_set_max_channels(sip_msg_t *msg, str *sclient, int max_chan)
 		return -1;
 	}
 
+	if(try_get_call_entry(&msg->callid->body, &call, &hts) == 0) {
+		LM_ERR("call-id[%.*s] already present\n",
+		msg->callid->body.len, msg->callid->body.s);
+		return -4;
+	}
+
 	LM_DBG("Setting up new call for client [%.*s], max-chan[%d], "
 		   "call-id[%.*s]\n",
 			sclient->len, sclient->s, max_chan, msg->callid->body.len,
@@ -1882,6 +1896,7 @@ static int ki_set_max_time(sip_msg_t *msg, str *sclient, int max_secs)
 {
 	credit_data_t *credit_data = NULL;
 	call_t *call = NULL;
+	hash_tables_t *hts = NULL;
 
 	if(parse_headers(msg, HDR_CALLID_F, 0) != 0) {
 		LM_ERR("Error parsing Call-ID");
@@ -1913,6 +1928,12 @@ static int ki_set_max_time(sip_msg_t *msg, str *sclient, int max_secs)
 		return -1;
 	}
 
+	if(try_get_call_entry(&msg->callid->body, &call, &hts) == 0) {
+		LM_ERR("call-id[%.*s] already present\n",
+		msg->callid->body.len, msg->callid->body.s);
+		return -4;
+	}
+
 	LM_DBG("Setting up new call for client [%.*s], max-secs[%d], "
 		   "call-id[%.*s]\n",
 			sclient->len, sclient->s, max_secs, msg->callid->body.len,
diff --git a/src/modules/cnxcc/doc/cnxcc.xml b/src/modules/cnxcc/doc/cnxcc.xml
index 686583f471f..3fc10feb8d5 100644
--- a/src/modules/cnxcc/doc/cnxcc.xml
+++ b/src/modules/cnxcc/doc/cnxcc.xml
@@ -23,15 +23,6 @@
 	    <email>carlos.ruizdiaz@gmail.com</email>
 	</address>
 	</author>
-        <editor>
-        <firstname>Jose Luis</firstname>
-        <surname>Verdeguer</surname>
-        <email>verdeguer@zoonsuite.com</email>
-        <affiliation><orgname>Zoon Suite</orgname></affiliation>
-        <address>
-                <email>verdeguer@zoonsuite.com</email>
-        </address>
-        </editor>
     </authorgroup>
     <copyright>
 	<year>2013</year>
@@ -41,10 +32,6 @@
 	<year>2014</year>
 	<holder>Carlos Ruiz Díaz, carlos@latamvoices.com</holder>
     </copyright>
-    <copyright>
-	<year>2018</year>
-	<holder>Jose Luis Verdeguer</holder>
-    </copyright>
 
     </bookinfo>
 
diff --git a/src/modules/cnxcc/doc/cnxcc_admin.xml b/src/modules/cnxcc/doc/cnxcc_admin.xml
index 0c26cb0a581..dbc4bf20b14 100644
--- a/src/modules/cnxcc/doc/cnxcc_admin.xml
+++ b/src/modules/cnxcc/doc/cnxcc_admin.xml
@@ -177,7 +177,7 @@ modparam("cnxcc", "credit_check_period", 1)
 
 					<listitem>
 						<para>
-							<emphasis>-2 - failed, credit value is less than initial pulse value</emphasis>
+							<emphasis>-4 - call-id already present for this client</emphasis>
 						</para>
 					</listitem>
 
@@ -345,6 +345,12 @@ if (!cnxcc_update_max_time("$var(client)", "$var(update_time)")) {
 						</para>
 					</listitem>
 
+					<listitem>
+						<para>
+							<emphasis>-4 - call-id already present for this client</emphasis>
+						</para>
+					</listitem>
+
 				</itemizedlist>
 			</para>
 			<example>
@@ -543,14 +549,21 @@ route[CNXCC]
 	$var(i_pulse)             = 30;
 	$var(f_pulse)             = 6;
 
-	if (!cnxcc_set_max_credit("$var(client)",
+
+	cnxcc_set_max_credit("$var(client)",
 			"$var(credit)",
 			"$var(connect_cost)",
 			"$var(cost_per_sec)",
 			"$var(i_pulse)",
-			"$var(f_pulse)")) {
-		xlog("Error setting up credit control");
-	}
+			"$var(f_pulse)");
+
+	switch ($?) {
+		case -1:
+			xerr("Error setting up credit control");
+			sl_send_reply("503", "Internal Server Error");
+		case -4:
+			xwarn("$ci already present for client $var(client)");
+	};
 }
 
 event_route[cnxcc:call-shutdown]