diff --git a/src/scanner.c b/src/scanner.c
index 765f2860..bffc2852 100644
--- a/src/scanner.c
+++ b/src/scanner.c
@@ -3457,7 +3457,7 @@ yaml_parser_scan_plain_scalar(yaml_parser_t *parser, yaml_token_t *token)
             if ((CHECK(parser->buffer, ':') && IS_BLANKZ_AT(parser->buffer, 1))
                     || (parser->flow_level &&
                         (CHECK(parser->buffer, ',')
-                         || CHECK(parser->buffer, '?') || CHECK(parser->buffer, '[')
+                         || CHECK(parser->buffer, '[')
                          || CHECK(parser->buffer, ']') || CHECK(parser->buffer, '{')
                          || CHECK(parser->buffer, '}'))))
                 break;