diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index cceb96f..0ea7898 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3363,7 +3363,7 @@
          * the remaining space in the datagram. */
         if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
         {
-            ret = ssl_get_maximum_datagram_size( ssl );
+            ret = ssl_get_remaining_space_in_datagram( ssl );
             if( ret < 0 )
                 return( ret );