| diff --git a/lib/openssl.c b/lib/openssl.c |
| index 3221a7e..0333fdf 100644 |
| --- a/lib/openssl.c |
| +++ b/lib/openssl.c |
| @@ -1141,7 +1141,7 @@ static int verify_cert_chain(X509_STORE *store, X509 *cert, STACK_OF(X509) * cha |
| ret = PTLS_ERROR_LIBRARY; |
| goto Exit; |
| } |
| - X509_STORE_CTX_set_purpose(verify_ctx, is_server ? X509_PURPOSE_SSL_SERVER : X509_PURPOSE_SSL_CLIENT); |
| + X509_STORE_CTX_set_purpose(verify_ctx, !is_server ? X509_PURPOSE_SSL_SERVER : X509_PURPOSE_SSL_CLIENT); |
| if (X509_verify_cert(verify_ctx) != 1) { |
| int x509_err = X509_STORE_CTX_get_error(verify_ctx); |
| switch (x509_err) { |
