i have problem in crawel

i set a new site on mirrormanager, and also i have report_mirror run successful ,but its crawel always told me that Ending crawl of <Host(2268 - mirrors.njupt.edu.cn)> with status 5,is there any help for me? what shows in log is 2017-04-27 17:20:44,949 - INFO - Worker '3a08f8e' starting on host <Host(2268 - mirrors.njupt.edu.cn)> 2017-04-27 17:21:01,346 - INFO - Crawling with URL None 2017-04-27 17:21:01,471 - INFO - Ending crawl of <Host(2268 - mirrors.njupt.edu.cn)> with status 5 2017-04-28 17:47:52,276 - INFO - Worker '2630be2' starting on host <Host(2268 - mirrors.njupt.edu.cn)> 2017-04-28 17:47:52,353 - INFO - Crawling with URL None 2017-04-28 17:47:52,408 - INFO - Ending crawl of <Host(2268 - mirrors.njupt.edu.cn)> with status 5