diff -Naur dovecot-2.2.19/src/lib-ssl-iostream/iostream-openssl-context.c dovecot-2.2.19-patched/src/lib-ssl-iostream/iostream-openssl-context.c
--- dovecot-2.2.19/src/lib-ssl-iostream/iostream-openssl-context.c	2015-01-29 17:01:15.000000000 +0100
+++ dovecot-2.2.19-patched/src/lib-ssl-iostream/iostream-openssl-context.c	2015-12-02 12:48:17.855220836 +0100
@@ -379,7 +379,7 @@
 	}
 
 	if (set->cert != NULL &&
-	    ssl_ctx_use_certificate_chain(ctx->ssl_ctx, set->cert) < 0) {
+	    ssl_ctx_use_certificate_chain(ctx->ssl_ctx, set->cert) == 0) {
 		*error_r = t_strdup_printf("Can't load SSL certificate: %s",
 			ssl_iostream_get_use_certificate_error(set->cert));
 		return -1;