[Home](./index.md) > [sip.js](./sip.js.md) > [InviteServerTransaction](./sip.js.inviteservertransaction.md) > [onTransportError](./sip.js.inviteservertransaction.ontransporterror.md) ## InviteServerTransaction.onTransportError() method First, the procedures in \[4\] are followed, which attempt to deliver the response to a backup. If those should all fail, based on the definition of failure in \[4\], the server transaction SHOULD inform the TU that a failure has occurred, and MUST remain in the current state. https://tools.ietf.org/html/rfc6026\#section-8.8 Signature: ```typescript protected onTransportError(error: Error): void; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | error | Error | | Returns: `void`