# HTTPS API Troubleshooting

* All HTTPS API are case-sensitive. Request path and query parameters letter-case shouldn't be changed.
* Make sure you're using the correct server. The correct host should be `blynk.cloud`
* In case you're getting the `Invalid token.` response from the HTTPS API,

  and you're sure the device auth token is correct - it could be a GEO DNS issue. 

{% hint style="info" %}
You can get the **Device auth token** in [Device info](https://docs.blynk.io/en/~/revisions/ynmC8lZ6FPocTYWigjcO/getting-started/activating-devices/manual-device-activation#step-3-getting-auth-token).
{% endhint %}

{% hint style="warning" %}
Due to current GeoDNS settings you need to put server address with suffix manually depending on your region:\
<https://fra1.blynk.cloud/> – Frankfurt\
<https://lon1.blynk.cloud/> – London\
<https://ny3.blynk.cloud/> – New York\
<https://sgp1.blynk.cloud/> – Singapore\
<https://blr1.blynk.cloud/> – Bangalore

The server region can be found in the right bottom corner of the web interface.
{% endhint %}