diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 795de9b7d..2090e33b4 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3375,7 +3375,7 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush )
          * 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 );