Why Does My n8n Telegram Trigger Work on Desktop but Not on Mobile?

Below is a summary of the situation and some troubleshooting steps you can take:

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Problem Description

When a document (both JPG and PDF) is uploaded via Telegram:

• Uploads work as expected when using the desktop app.
• No trigger fires when uploading from a cellphone.
• No error message is returned—the trigger simply doesn’t run.

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Points to Consider

1. Event Types and Payloads
   The Telegram Trigger node listens for incoming update events (e.g. messages with files). Although desktop and mobile uploads should generate similar events, it’s possible that the mobile client sends a slightly different payload or handles file types differently. Compare the payloads (if possible) when triggering from desktop versus cellphone to see if there are differences in the data structure or file metadata.

2. Node Configuration
   Ensure that the Telegram Trigger node has no filters or limitations set that might exclude certain file types or update events. Verify that it’s configured to handle document uploads appropriately.

3. Telegram Behavior
   Telegram’s mobile app could process files differently (for example, compressing or tagging images/files differently) and that might affect how the update is formatted.

4. External Factors
   Since you’re using n8n Cloud, the webhook and connectivity seem to work well (as shown by the successful desktop trigger). However, if any differences exist in how Telegram formats or sends updates originating from mobile devices, this might require further inspection of the incoming update payload.

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Recommended Troubleshooting Steps

• Inspect the Incoming Payload:
  Temporarily modify your workflow or add a debugging step that logs the entire payload received by the Telegram Trigger node. Do this for both a desktop and cellphone upload. This can highlight any differences in the update structure.

• Check Node Filters and Event Types:
  Review your Telegram Trigger node settings to ensure it isn’t filtering out a particular type of update that might be sent by mobile devices. Confirm that document uploads aren’t being inadvertently excluded.

• Consult Telegram’s API Documentation:
  Review the Telegram Bot API reference to understand how file uploads from different platforms (desktop vs mobile) are handled. This might provide additional clues as to any disparities in how updates are reported.

• Test With Different File Types/Sizes:
  Although you’ve tried JPG and PDF, test with other file formats if possible. This can help rule out if it’s an issue tied to specific formats or sizes that might be treated differently on mobile.

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If after these steps the issue persists, consider reaching out to n8n Cloud support with details (and sample payloads, if possible) from your debugging tests so they can help determine if this is an edge-case behavior with document uploads on mobile devices.