diff --git a/configs/config-ccm-psk-tls1_2.h b/configs/config-ccm-psk-tls1_2.h
index a783e6b73b..c9b58dd538 100644
--- a/configs/config-ccm-psk-tls1_2.h
+++ b/configs/config-ccm-psk-tls1_2.h
@@ -81,7 +81,7 @@
  * both ends of the connection!  (See comments in "mbedtls/ssl.h".)
  * The optimal size here depends on the typical size of records.
  */
-#define MBEDTLS_SSL_MAX_CONTENT_LEN             512
+#define MBEDTLS_SSL_MAX_CONTENT_LEN             1024
 
 #include "mbedtls/check_config.h"