If you encounter issues with the CGM app, you may see one of the following error codes or messages on your watchface. This guide will help you diagnose and resolve common problems.
Click any error to jump to detailed troubleshooting:
Message: "Failed to authenticate" or "Auth Failed"
Cause: Your Dexcom Share credentials are incorrect or the wrong region is selected.
Solution:
Message: "Maximum authentication attempts exceeded"
Cause: Too many failed login attempts in a short period.
Solution:
Message: "Session ID not found"
Cause: Your session has expired or was never created.
Solution:
Message: "Session not active or timed out"
Cause: Your Dexcom Share session has expired (typically after 24 hours).
Solution:
Message: "Username must be non-empty string"
Cause: No username has been entered in settings.
Solution:
Message: "Password must be non-empty string"
Cause: No password has been entered in settings.
Solution:
Message: "Invalid or malformed JSON in server response"
Cause: The Dexcom server sent an unexpected or corrupted response.
Solution:
Message: "Unknown error code in server response"
Cause: The Dexcom API returned an error code that the app doesn't recognize.
Solution:
Message: "Unexpected server response"
Cause: The Dexcom server responded in an unexpected way.
Solution:
These errors originate from the Garmin Communications API when the watch encounters network, Bluetooth, or communication issues.
Code: UNKNOWN_ERROR
Cause: An unknown error has occurred.
Solution: Restart your watch and check connectivity.
Code: BLE_ERROR
Cause: A generic BLE error has occurred.
Solution:
Code: BLE_HOST_TIMEOUT
Cause: Timed out waiting for a response from the host (phone).
Solution:
Code: BLE_SERVER_TIMEOUT
Cause: Timed out waiting for a response from a server.
Solution:
Code: BLE_NO_DATA
Cause: Response contained no data.
Solution: Wait for next update cycle. Check Dexcom app has readings.
Code: BLE_REQUEST_CANCELLED
Cause: The request was cancelled by the system.
Solution: Normal behavior - app will retry automatically.
Code: BLE_QUEUE_FULL
Cause: Too many requests have been made.
Solution:
Code: BLE_REQUEST_TOO_LARGE
Cause: Serialized input data for the request was too large.
Solution: Contact developer - this is an app issue.
Code: BLE_UNKNOWN_SEND_ERROR
Cause: Send failed for an unknown reason.
Solution:
Code: BLE_CONNECTION_UNAVAILABLE
Cause: No BLE connection is available.
Solution:
Code: INVALID_HTTP_HEADER_FIELDS_IN_REQUEST
Cause: Request contained invalid http header fields.
Solution: Contact developer - this is an app configuration issue.
Code: INVALID_HTTP_BODY_IN_REQUEST
Cause: Request contained an invalid http body.
Solution: Contact developer - this is an app issue.
Code: INVALID_HTTP_METHOD_IN_REQUEST
Cause: Request used an invalid http method.
Solution: Contact developer - this is an app issue.
Code: NETWORK_REQUEST_TIMED_OUT
Cause: Request timed out before a response was received.
Solution:
Code: STORAGE_FULL
Cause: Filesystem too full to store response data.
Solution:
Meaning: No data available or app not configured.
Solution:
Meaning: The last reading is more than 10 minutes old.
Solution:
More Resources: Check the FAQ for common questions or return to Introduction.