> For the complete documentation index, see [llms.txt](https://docs.teranode.group/nchain-event/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.teranode.group/nchain-event/troubleshooting/error-codes.md).

# Error Codes

The Event REST API endpoints may emit these errors during operation:

<table><thead><tr><th>Error Code</th><th width="100">Endpoints</th><th>Meaning - mitigation</th></tr></thead><tbody><tr><td>CONTENT_IS_REQUIRED</td><td>Write / Verify / Create / Update</td><td>No content has been supplied to submit to the blockchain, but it is required - try again</td></tr><tr><td>CONTENT_LENGTH_LIMIT_EXCEEDED</td><td>Write / Verify / Create / Update</td><td>The size of the content exceeds a configuration setting - make the payload smaller or contact us for an update</td></tr><tr><td>ENCODER_ARGUMENT_MISSING</td><td>Write / Verify / Create / Update</td><td>No encoder argument was supplied - try this: SHA256(any-salt-you-want)</td></tr><tr><td><p>ENCODER_FINGERPRINT_MISSING</p><p>ENCODER_SHA256_MISSING</p></td><td>Write / Verify / Create / Update</td><td>A fingerprint encoder is required for this configuration - specify a SHA256 encoder or contact us for an update</td></tr><tr><td>ENCODE_PARAM_INVALID</td><td>Write / Verify / Create / Update</td><td>The parameter supplied to Encode is erroneous - check the syntax above</td></tr><tr><td>INCORRECT_EVENT_TRANSACTION_TYPE</td><td>Delete</td><td>The delete operation does not accept any content - perform an update followed by a delete</td></tr><tr><td>INVALID_NAVIGATION_TRANSACTION_TYPE</td><td>Navigate</td><td>It is only possible to navigate us Event linked records - try again</td></tr><tr><td><p>NOT_A_DATA_TRANSACTION</p><p>NOT_AN_EVENT_TRANSACTION</p></td><td>Get (Link) Location Status / Read (Link) Record</td><td>The supplied TX_ID parameter appears to be invalid - check and try again</td></tr><tr><td>NOT_LINKED_RECORDS_END</td><td>Update / Delete</td><td>It is only possible to update or delete the last location in linked records - use the last location</td></tr><tr><td>PREV_TX_ID_PARAM_MISSING</td><td>Verify / Delete</td><td>You must supply the previous TX_ID to verify the linked record - try again</td></tr><tr><td>TX_ID_PARAM_INVALID</td><td>Get (Link) Location Status / Read (Link) Record</td><td>The supplied TX_ID parameter appears to be invalid - check and try again</td></tr><tr><td>TX_NOT_LINKABLE</td><td>Update / Delete</td><td>The location refers to a transaction that cannot be updated or deleted - try again with the location of a valid unlinked transaction</td></tr><tr><td>UNKNOWN_ENCODER</td><td>Write / Verify / Create / Update</td><td>The supplied encoder appears to be invalid - try again or contact us for an upgrade</td></tr></tbody></table>