diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 4b27831..e6488c0 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -354,7 +354,7 @@
 #endif
 
 #if defined(MBEDTLS_LMS_C) &&                                          \
-    ( !defined(MBEDTLS_PSA_CRYPTO_C) && !defined(PSA_WANT_ALG_SHA256) )
+    ! ( defined(MBEDTLS_PSA_CRYPTO_C) && defined(PSA_WANT_ALG_SHA256) )
 #error "MBEDTLS_LMS_C requires MBEDTLS_PSA_CRYPTO_C and PSA_WANT_ALG_SHA256"
 #endif