diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 4d92274..2c0c4dd 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -110,6 +110,7 @@
 #define MBEDTLS_ERR_SSL_UNEXPECTED_RECORD                 -0x6700  /**< Record header looks valid but is not expected. */
 #define MBEDTLS_ERR_SSL_NON_FATAL                         -0x6680  /**< The alert message received indicates a non-fatal error. */
 #define MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH               -0x6600  /**< Couldn't set the hash for verifying CertificateVerify */
+#define MBEDTLS_ERR_SSL_BAD_CONFIG                        -0x5E80  /**< Invalid value in SSL config */
 
 /*
  * Various constants