[E][WiFiGeneric.cpp:641] hostByName(): DNS Failed for CE

[wegunterjr]

Hardware:

Board: ESP32 Dev Module
Core Installation/update date: version 3.5.4/ says most up to date (Seems wrong?)
IDE name: Platform.io
Flash Frequency: 40Mhz
Upload Speed: 115200

Description:

Not sure what is happening, but this is the error I am getting:

[E][WiFiGeneric.cpp:641] hostByName(): DNS Failed....
`

I think it has to do with calling WiFi.begin(sid, pwd), but wanted to verify..

[jontay81]

Hardware:
Boards: Adafruit Feather ESP32, HiLetgo ESP32 Dev Board
Core Installation/update date: July 7. 2018 install date
IDE name: VSCode / Arduino Extension
Flash Frequency: 80Mhz
Upload Speed: 115200

Description:
Having this same error when scanning for BLE signals then issuing a POST request over WiFi to a LAN server with DNS setup through my router.

It occurs intermittently - somewhere between 1 and 4 hours after reset. After one occurrence, the error occurs every time the device attempts a POST request.

Haven't tested on an internet DNS lookup or using a LAN IP address yet.

[V][HTTPClient.cpp:140] beginInternal(): url: http://dev-wifi:3100/api/beacon
[D][HTTPClient.cpp:181] beginInternal(): host: dev-wifi port: 3100 url: /api/beacon
[E][WiFiGeneric.cpp:659] hostByName(): DNS Failed for dev-wifi
[D][HTTPClient.cpp:846] connect(): failed connect to dev-wifi:3100
[W][HTTPClient.cpp:1124] returnError(): error(-1): connection refused

I suppose there's a way to catch the error and reset the wifi connection that might work. I'll update this if I find a workaround.

[copercini]

I'm also getting it during or after BLE scans

[copercini]

This seems to happen here when a task has a priority too high (over 4) or may the wifi code isn't pinned to arduino core

[copercini]

I think I found the problem: there is a task that handle the hostByName() command here

This task has priority 2, so if you create other tasks with more priority, the reported bug will appear

[roger-zacharczyk]

Having the same issue despite the update. The message "STA IP..., GW... " is logged, though, so it gets all the addresses needed.

[roger-zacharczyk]

Nevermind that. I passed "http://hostname" instead of just "hostname".