# Conection failed / Sensors disappearing

**URL:** <https://forum.sensor.community/t/conection-failed-sensors-disappearing/772>\
**Category:** Uncategorized\
**Created:** [August 6, 2021, 3:37pm UTC](https://forum.sensor.community/t/conection-failed-sensors-disappearing/772 "2021-08-06T15:37:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rotor-studio](https://forum.sensor.community/user_avatar/forum.sensor.community/rotor-studio/32/457_2.png) [@rotor-studio](https://forum.sensor.community/u/rotor-studio)\
**Post date:** [August 6, 2021, 3:37pm UTC](https://forum.sensor.community/t/conection-failed-sensors-disappearing/772/1 "2021-08-06T15:37:14Z")

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Hello dear Community! I have a trouble with some of my sensors and the connection to the database and i’m looking for a solution  
The status of these sensors look like this:

 ![127219407-d2b3390d-2fe3-4405-be57-dfdf57a17325](https://forum.sensor.community/uploads/default/original/1X/3a31cecb5bee12b16246052dc487abf98b1a163d.png)  
And is happen with my own arduino compilation and the standar firmware. I don’t now but i have the suspicion that maybe is a ban from the database sistem or my router configuration or company behind (i don’t remember any extra configuration)  
Thanks! 🙂

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**Author:** ![ricki-z](https://forum.sensor.community/user_avatar/forum.sensor.community/ricki-z/32/215_2.png) [@ricki-z](https://forum.sensor.community/u/ricki-z)\
**Post date:** [August 7, 2021, 4:42pm UTC](https://forum.sensor.community/t/conection-failed-sensors-disappearing/772/2 "2021-08-07T16:42:54Z")

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Hi,  
there are no automatic bans on our database systems for API requests.  
Could you please check if the DNS resolution is working for DHCP clients in the same network the sensor is in?  
Hostnames are api.sensor.community for the Sensor.Community API and [api-rrd.madavi.de](http://api-rrd.madavi.de) for the Mdavi API.

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<div class="post-metadata">

**Author:** ![rotor-studio](https://forum.sensor.community/user_avatar/forum.sensor.community/rotor-studio/32/457_2.png) [@rotor-studio](https://forum.sensor.community/u/rotor-studio)\
**Post date:** [August 11, 2021, 11:21am UTC](https://forum.sensor.community/t/conection-failed-sensors-disappearing/772/3 "2021-08-11T11:21:24Z")

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Hi @ricki-z , thanks for you idea. I don´t know exactly what you mean with DNS resolution and i cant fin any tip for my router about this but i have suspicion that something happen with this. For example: I can connect to api.sensor.community with a HTTP 200 OK response, only trough a VPN. And also with the forum, etc.  
I dont have any extra configuration on my router( routers, i have two different sensors with a different connections from the same company and the same problem), i will call to my company and try to discover what happen.  
I will return with what I can discover 😉