diff --git a/examples/server-tcp.c b/examples/server-tcp.c
index 4688e61..1f5a551 100644
--- a/examples/server-tcp.c
+++ b/examples/server-tcp.c
@@ -130,9 +130,8 @@ int main(int argc, char* argv[]) {
 
         err = nmbs_server_poll(&nmbs);
         if (err != NMBS_ERROR_NONE) {
-            fprintf(stderr, "Error polling modbus connection - %s\n", nmbs_strerror(err));
-            // In a more complete example, we should handle this error by closing the connection from our side
-            break;
+            fprintf(stderr, "Error on modbus connection - %s\n", nmbs_strerror(err));
+            // In a more complete example, we would handle this error by checking its nmbs_error value
         }
     }
 
diff --git a/nanomodbus.c b/nanomodbus.c
index 607f8b2..fd099d5 100644
--- a/nanomodbus.c
+++ b/nanomodbus.c
@@ -249,7 +249,7 @@ static nmbs_error recv_msg_footer(nmbs_t* nmbs) {
         uint16_t recv_crc = get_2(nmbs);
 
         if (recv_crc != crc)
-            return NMBS_ERROR_TRANSPORT;
+            return NMBS_ERROR_CRC;
     }
 
     DEBUG("\n");
@@ -315,10 +315,10 @@ static nmbs_error recv_msg_header(nmbs_t* nmbs, bool* first_byte_received) {
         nmbs->msg.fc = get_1(nmbs);
 
         if (protocol_id != 0)
-            return NMBS_ERROR_TRANSPORT;
+            return NMBS_ERROR_INVALID_TCP_MBAP;
 
         if (length > 255)
-            return NMBS_ERROR_TRANSPORT;
+            return NMBS_ERROR_INVALID_TCP_MBAP;
     }
 
     return NMBS_ERROR_NONE;
@@ -1288,6 +1288,12 @@ nmbs_error nmbs_receive_raw_pdu_response(nmbs_t* nmbs, void* data_out, uint32_t
 #ifndef NMBS_STRERROR_DISABLED
 const char* nmbs_strerror(nmbs_error error) {
     switch (error) {
+        case NMBS_ERROR_INVALID_TCP_MBAP:
+            return "invalid TCP MBAP received";
+
+        case NMBS_ERROR_CRC:
+            return "invalid CRC received";
+
         case NMBS_ERROR_TRANSPORT:
             return "transport error";
 
diff --git a/nanomodbus.h b/nanomodbus.h
index 323be79..778ad9d 100644
--- a/nanomodbus.h
+++ b/nanomodbus.h
@@ -54,6 +54,8 @@
  */
 typedef enum nmbs_error {
     // Library errors
+    NMBS_ERROR_INVALID_TCP_MBAP = -6, /**< Received invalid TCP MBAP */
+    NMBS_ERROR_CRC = -5,              /**< Received invalid CRC */
     NMBS_ERROR_TRANSPORT = -4,        /**< Transport error */
     NMBS_ERROR_TIMEOUT = -3,          /**< Read/write timeout occurred */
     NMBS_ERROR_INVALID_RESPONSE = -2, /**< Received invalid response from server */