diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 91e6f4e..5ae9f7c 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1295,6 +1295,7 @@
      */
     /* If we've settled on a PSK-based exchange, parse PSK identity ext */
     if( mbedtls_ssl_tls13_some_psk_enabled( ssl ) &&
+        mbedtls_ssl_conf_tls13_some_psk_enabled( ssl ) &&
         ( ssl->handshake->extensions_present & MBEDTLS_SSL_EXT_PRE_SHARED_KEY ) )
     {
         ssl->handshake->update_checksum( ssl, buf,