Entire site doesn't work after clearing caches

Try the following:

1. check php version
2. clear cache tables manuallly

TRUNCATE `cachetags`;
TRUNCATE `cache_advagg`;
TRUNCATE `cache_bootstrap`;
TRUNCATE `cache_config`;
TRUNCATE `cache_container`;
TRUNCATE `cache_data`;
TRUNCATE `cache_default`;
TRUNCATE `cache_discovery`;
TRUNCATE `cache_dynamic_page_cache`;
TRUNCATE `cache_entity`;
TRUNCATE `cache_menu`;
TRUNCATE `cache_page`;
TRUNCATE `cache_render`;
TRUNCATE `cache_toolbar`;

1. use "drush cc all" in drupal 7 or "drush cr" in drupal ^8