Stuck on a 500 Internal Server Error when attempting to inject a proactive notification into a cold web messaging session via the Genesys Cloud REST API. The flow involves retrieving an archived guest profile using GET /api/v2/conversations/webmessaging/guests/{id} and immediately posting a message via POST /api/v2/conversations/webmessaging/guests/{id}/messages with the following payload: {"content": "Your appointment reminder.", "type": "text"}. The request returns HTTP 500 with the body: {"code": "internal_server_error", "message": "Failed to send message to guest", "details": "Guest session is inactive or expired"}. I have verified that the id corresponds to a valid guest record from the previous day, and the OAuth token has the webmessaging:guest scope. However, the documentation implies that proactive messaging requires an active WebSocket connection or a specific re-engagement state that is not clearly defined in the standard guest object response. I am orchestrating this through a Custom Data Action using the GetRESTProxy snippet in CXone Studio, mapping the guest ID from a prior interaction table. The timeout is set to 3000ms, which is sufficient for a simple POST. Is there a specific header, such as X-Genesys-Feature, or a query parameter like ?force=true that bypasses the session state check? Alternatively, does the API require a prior PUT to reactivate the guest session before allowing message injection? The current implementation fails consistently after the session duration exceeds 24 hours, suggesting a hard limit on the guest resource state that prevents direct messaging without re-establishing a live connection. I need a code-level workaround to push notifications to these dormant guests without forcing them to re-initiate the chat flow manually. The JSON response lacks detailed stack traces, making it difficult to determine if this is a backend validation error or a connection pool issue.
Check your OAuth scopes. The 500 error often masks a 403 if webmessaging:guest:message is missing. Ensure the token used for the POST has this scope. Here is the corrected payload structure:
{
"content": "Your appointment reminder.",
"type": "text"
}You need to verify the guest’s active session status before attempting the POST. The 500 error usually indicates the platform cannot locate a valid, open conversation for that guestId. If the guest session expired or was archived, the API rejects the message injection.
Check the status field in the GET response. It must be active. If it is archived or closed, you cannot send messages directly. You must initiate a new conversation first.
Here is the Node.js check using PureCloudPlatformClientV2:
const { ConversationsApi } = require('@genesyscloud/genesyscloud');
const conversationsClient = new ConversationsApi();
async function sendProactiveMessage(guestId) {
const guest = await conversationsClient.getWebmessagingGuest(guestId);
if (guest.body.status !== 'active') {
throw new Error('Guest session is not active. Cannot send message.');
}
// Proceed with POST /api/v2/conversations/webmessaging/guests/{guestId}/messages
}
Also ensure your OAuth token includes webmessaging:guest:message. Missing scopes often bubble up as 500s in legacy clients.
Have you tried inspecting the actual response body from the 500 error? Often the platform returns a specific validation error message inside the JSON payload that explains why the message injection failed. The suggestion above mentions session status, which is valid, but in .NET SDK v5, I also see this when the guestId does not match the internal routing context or if the conversation type is not strictly webmessaging.
I use HttpClient directly for these low-level operations because the SDK sometimes obscures the detailed error response in the exception. Here is how I verify the session state before sending:
var response = await httpClient.GetAsync($"/api/v2/conversations/webmessaging/guests/{guestId}");
var guest = await response.Content.ReadFromJsonAsync<Guest>();
if (guest?.Status != "active")
{
// Do not send message
throw new InvalidOperationException("Guest session is not active.");
}
Note: If the guest is archived, you must start a new conversation ID. You cannot inject messages into closed sessions via the Guest API.
I normally fix this by ensuring the conversationId is explicitly linked in the message payload, even when addressing the guest endpoint directly. The platform often rejects the injection if the routing context isn’t strictly defined, especially for proactive pushes. The suggestion above about session status is valid, but the 500 error frequently stems from a missing conversationId reference in the POST body.
{
"content": "Your appointment reminder.",
"type": "text",
"conversationId": "your-active-conversation-id"
}
If you are using the PureCloudPlatformClientV2 SDK, verify that the WebMessagingGuestMessage object includes the conversation ID. Without it, the API cannot resolve the target channel for the message injection. I’ve seen this fail silently with a 500 when the guest is active but the conversation object isn’t fully initialized in the current scope. Always include the ID to avoid ambiguity.
Note: Ensure your OAuth token includes webmessaging:guest:message and conversation:read scopes. Missing scopes often return 403, but misconfigured payloads can trigger 500s during validation.