diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 496f7e1..735a1e4 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -668,7 +668,7 @@
       !defined(MBEDTLS_SSL_CONF_ENFORCE_EXTENDED_MASTER_SECRET) ) || \
     ( !defined(MBEDTLS_SSL_CONF_EXTENDED_MASTER_SECRET) &&           \
       defined(MBEDTLS_SSL_CONF_ENFORCE_EXTENDED_MASTER_SECRET) )
-#define "MBEDTLS_SSL_CONF_EXTENDED_MASTER_SECRET and MBEDTLS_SSL_CONF_ENFORCE_EXTENDED_MASTER_SECRET must be defined together."
+#error "MBEDTLS_SSL_CONF_EXTENDED_MASTER_SECRET and MBEDTLS_SSL_CONF_ENFORCE_EXTENDED_MASTER_SECRET must be defined together."
 #endif
 
 #if ( defined(MBEDTLS_SSL_CONF_SEND) &&                 \
@@ -680,14 +680,14 @@
     ( defined(MBEDTLS_SSL_CONF_RECV_TIMEOUT) &&         \
       !( defined(MBEDTLS_SSL_CONF_SEND) &&              \
          defined(MBEDTLS_SSL_CONF_RECV) ) )
-#define "MBEDTLS_SSL_CONF_SEND/RECV/RECV_TIMEOUT must be defined simultaneously"
+#error "MBEDTLS_SSL_CONF_SEND/RECV/RECV_TIMEOUT must be defined simultaneously"
 #endif
 
 #if ( defined(MBEDTLS_SSL_CONF_GET_TIMER) &&            \
       !defined(MBEDTLS_SSL_CONF_SET_TIMER) ) || \
     ( !defined(MBEDTLS_SSL_CONF_GET_TIMER) &&           \
       defined(MBEDTLS_SSL_CONF_SET_TIMER) )
-#define "MBEDTLS_SSL_CONF_GET_TIMER and MBEDTLS_SSL_CONF_SET_TIMER must be defined together."
+#error "MBEDTLS_SSL_CONF_GET_TIMER and MBEDTLS_SSL_CONF_SET_TIMER must be defined together."
 #endif
 
 #if defined(MBEDTLS_SSL_TICKET_C) && !defined(MBEDTLS_CIPHER_C)