----------------------------- **While I generate an answer, here are some sources that might be helpful**: * [List Calls]() * [Get Call]() * [Create Phone Call]() * [Call Ended Reason]() -----------------------------

### Answer Encountering an "unknown-error" during calls that extend beyond 10 minutes can be perplexing. The "unknown-error" message typically suggests an unexpected issue occurred during the call's execution. Although the official documentation does not explicitly mention errors related to call duration, a similar issue was discussed in a Discord forum, where a user faced the "unknown-error" due to an expired API key [(1)]() . While this may not be the direct cause of your issue, it highlights how sometimes errors not directly related to the call's length can impact call performance. Additionally, it's worth noting that server-side issues such as a "server-shutdown" error have been reported for calls attempting to exceed a certain duration, although these are supposed to be governed by the

maxDurationSeconds

parameter [(2)]() . Given the nature of "unknown-error", it's advisable to review the call setup, including any time-related parameters or server configurations that might impact long-duration calls. Checking the expiration and validity of all related API keys or services used during the call could also provide some insights. Unfortunately, without more specific logs or error messages, it's challenging to provide a precise solution.