3.5 Site down recently and randomly

Hi, we have a nop 3.5 site hosted in our server for 4 years now, but 1 month ago the site randomly goes down, without apparently any reason.

We have monitored the site on site24x7.com and when it alerts the site is down and we check, the site is blank, no typical error page : "we are sorry an internal error ocurred"..

What is surprisin, is that on IIS, google/bing bot entries, keep entering without error, but for example if we check in that moment with site24x7.com, the entry on IIS log is saved but gives a 301 redirect error.

The site is https, and we see that the site24x7.com request and nopcommerce keep alive are entering both through port 80, maybe the redirection in that moment is failing...?

How can we log more?

Thank you so much.

Regards.

In the log you can see that our monitor alert recives a 301 error, but other request are coming correctly with a 200 message:

2020-01-13 16:06:39 87.106.49.130 GET / - 80 - 63.143.42.251 Mozilla/5.0+(compatible;+UptimeRobot/2.0;+http://www.uptimerobot.com/) http://www.suministrosurquiza.com 301 0 64 50578
2020-01-13 16:06:44 87.106.49.130 GET /puas-carga-pacas - 443 - 83.56.157.108 Mozilla/5.0+(Windows+NT+6.3;+WOW64;+Trident/7.0;+rv:11.0)+like+Gecko https://www.bing.com/search?q=p%C3%BAa+cargapacas+1m&qs=n&form=QBRE&sp=-1&ghc=1&pq=p%C3%BAa+cargapacas+1m&sc=1-17&sk=&cvid=2418681019144FD784BA125925784828 200 0 64 122422
2020-01-13 16:06:46 87.106.49.130 GET /tapa-pequeña-k-35-hoz-244 - 443 - 114.99.177.16 Mozilla/5.0(Linux;Android+5.1.1;OPPO+A33+Build/LMY47V;wv)+AppleWebKit/537.36(KHTML,link+Gecko)+Version/4.0+Chrome/43.0.2357.121+Mobile+Safari/537.36+LieBaoFast/4.51.3 - 200 0 64 100703
2020-01-13 16:07:00 87.106.49.130 GET /mandil-delantal-soldador-888-md - 443 - 114.107.151.196 Mozilla/5.0(Linux;U;Android+5.1.1;zh-CN;OPPO+A33+Build/LMY47V)+AppleWebKit/537.36(KHTML,like+Gecko)+Version/4.0+Chrome/40.0.2214.89+UCBrowser/11.7.0.953+Mobile+Safari/537.36 - 200 0 64 108937
2020-01-13 16:07:00 87.106.49.130 GET /brazo-desplazado-derecho-mediano-sola - 443 - 114.223.166.62 Mozilla/5.0(Linux;U;Android+5.1.1;zh-CN;OPPO+A33+Build/LMY47V)+AppleWebKit/537.36(KHTML,like+Gecko)+Version/4.0+Chrome/40.0.2214.89+UCBrowser/11.7.0.953+Mobile+Safari/537.36 - 200 0 64 112547
2020-01-13 16:07:01 87.106.49.130 GET /keepalive/index - 80 - 87.106.49.130 - - 200 0 0 52140
2020-01-13 16:07:06 87.106.49.130 GET /triangulo-agricarb-etg-2323md-derecha-gregoire-besson - 443 - 223.245.213.102 Mozilla/5.0(Linux;Android+5.1.1;OPPO+A33+Build/LMY47V;wv)+AppleWebKit/537.36(KHTML,link+Gecko)+Version/4.0+Chrome/43.0.2357.121+Mobile+Safari/537.36+LieBaoFast/4.51.3 - 200 0 64 114656
2020-01-13 16:07:10 87.106.49.130 GET /arrancador-telwin-drive-9000 - 443 - 59.63.75.36 Mozilla/5.0(Linux;Android+5.1.1;OPPO+A33+Build/LMY47V;wv)+AppleWebKit/537.36(KHTML,link+Gecko)+Version/4.0+Chrome/43.0.2357.121+Mobile+Safari/537.36+LieBaoFast/4.51.3 - 200 0 64 116390
2020-01-13 16:07:13 87.106.49.130 GET /brazo-cultivador-caracol-bellota-2480-20x20-izquierda - 443 - 66.249.64.70 Mozilla/5.0+(compatible;+Googlebot/2.1;++http://www.google.com/bot.html) - 200 0 0 131781
2020-01-13 16:07:17 87.106.49.130 GET /nivel-aluminio-bellota-50101-40 - 443 - 60.169.218.227 Mozilla/5.0(Linux;Android+5.1.1;OPPO+A33+Build/LMY47V;wv)+AppleWebKit/537.36(KHTML,link+Gecko)+Version/4.0+Chrome/42.0.2311.138+Mobile+Safari/537.36+Mb2345Browser/9.0 - 200 0 64 82547
2020-01-13 16:07:24 87.106.49.130 GET /pulverizador-matabi-super-agro-16 gclid=CjwKCAiAx_DwBRAfEiwA3vwZYiLkS608ChRml3pDcrYOFbjbDfEoizoGsKTi844nCPzATXoR981BuhoC74IQAvD_BwE 443 - 84.78.244.66 Mozilla/5.0+(Linux;+Android+7.1.2;+Redmi+Note+5A+Prime)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Chrome/79.0.3945.116+Mobile+Safari/537.36 https://www.google.com/ 200 0 64 96906
2020-01-13 16:07:41 87.106.49.130 GET /estufa-jardin-terraza-a-gas - 443 - 113.220.94.132 Mozilla/5.0+(Linux;+Android+7.0;+FRD-AL00+Build/HUAWEIFRD-AL00;+wv)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Version/4.0+Chrome/53.0.2785.49+Mobile+MQQBrowser/6.2+TBS/043602+Safari/537.36+MicroMessenger/6.5.16.1120+NetType/WIFI+Language/zh_CN - 404 0 121 133687
2020-01-13 16:07:53 87.106.49.130 GET /content/images/thumbs/0013408_polea-con-soporte-canal-redondo.jpeg - 443 - 84.236.179.202 Mozilla/5.0+(Linux;+Android+7.1.1;+Aquaris+U+Plus+Build/NMF26F;+wv)+AppleWebKit/537.36+(KHTML,+like+Gecko)+Version/4.0+Chrome/79.0.3945.116+Mobile+Safari/537.36+GSA/10.90.16.21.arm https://www.google.com/blank.html 200 0 0 1359
2020-01-13 16:08:16 87.106.49.130 GET / - 80 - 54.67.10.127 Mozilla/5.0+(compatible;+UptimeRobot/2.0;+http://www.uptimerobot.com/) http://www.suministrosurquiza.com 301 0 64 99797

Maybe this can help you
https://airbrake.io/blog/http-errors/301-moved-permanently

New York wrote:

I read the article, but is focus mostly on apache and nginx...
I didn't mean it is something only related with that 301 error, but what else to look or how to monitor for the next time the site goes down.

Thank you for your answer.

amibumpig wrote:
Yes, but the general issue applies
"code generally indicates an issue on the actual web server hosting your application."
"check the configuration files for your web server software for unintentional redirect instructions."

Is the site on premises or hosted?  If hosted, then speak to their tech support.

Are you using SSL / HTTPS?    Are non-https:// requests causing the problem?

New York wrote:

It is hosted on our servers,
Yes we are using SSL,
No, it redirects correctly, for example: http://www.suministrosurquiza.com/hacha-vizcaina-con-mango-bellota-8130