Recently I tried to make a weather station with this tutorial. I created a device in Losant and created key and value. But when I boot my ESP8266 I get
Authenticating Device…Failed to authorize device to Losant.
Invalid credentials to Losant: Please double-check the device ID, access key, and access secret.
But I checked a few times and it’s ok. How to fix this?
The next thing to check is your application’s communication log. This will log all communication occurring within your application, including authentication attempts.
As long as the device ID is correct or the key/secret are correct, the log will display a message with additional information. This is only a real-time log, so you’ll first want to open the browser to the application overview page, then attempt to connect. If you don’t see any information logged, this means both the device ID and the application key/secret are incorrect. Basically we couldn’t figure out which application the device belonged to based on the authentication information provided.
You can also PM me your source code and I can take a quick look at the device ID, key, and secret to make sure they look correct. It’s very common to have those swapped or copy/pasted incorrectly into the source code.
Turns out I’ve mistaken tag key with acces key. 
Glad you got it figured out!
Does not work, have tried many times with the correct deviceID, key/secret… also have switch to secret/key and always get the same error message:
Authenticating Device…Failed to authorize device to Losant.
Invalid credentials to Losant: Please double-check the device ID, access key, and access secret.
Nothing is in the device log
Can you please PM me your source code? I’ll take a look and see if anything jumps out.
I have found the error… my mistake… i have confused device tag (key/value) with the security option “Access Key”.