php curl 首次无法post服务端

phpcurl

应用端PHP，服务端Java

长时间不打开网站，再次访问网站时，应用端用curl调用服务端接口，无法访问。
第二次又正常。

 {"url":"xxx","content_type":null,"http_code":0,"header_size":0,"request_size":337,"filetime":-1,"ssl_verify_result":0,"redirect_count":0,"total_time":15.019257,"namelookup_time":0.00327,"connect_time":0.003374,"pretransfer_time":0.003375,"size_upload":190,"size_download":0,"speed_download":0,"speed_upload":12,"download_content_length":-1,"upload_content_length":0,"starttransfer_time":0,"redirect_time":0,"certinfo":[]}