SolarWinds Platform alert HTTP POST actions fail with TLS/SSL certificate trust errors when using an outbound proxy

2/3/2026 7:57 AM

2/3/2026 5:00 PM

Observed behavior:

Alert conditions still trigger as expected.
The HTTP POST alert actions fail, and incidents/tickets are not created in the external ITSM or ticketing platform.

Browser test behavior:

A browser GET from the SolarWinds Platform server directly to the ITSM API URL:
Shows a normal padlock (no certificate warning).
Returns HTTP 405 (Method Not Allowed), which is expected for a GET on a POST‑only endpoint.
Does not reproduce the TLS/SSL trust error.

PowerShell test behavior:

A PowerShell POST from the SolarWinds Platform server to the same ITSM API URL fails with:
The same AuthenticationException and "remote certificate is invalid" errors.
This indicates the failure occurs in the Windows/.NET TLS stack, including the proxy path, rather than only in the browser.

Errors in logs:

Action Execution Alerting Logs:
"The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel."
"System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure."

 

 

Network Performance Monitor

1. The SolarWinds Platform is configured to send HTTP POST requests to the external ticketing API via a specific corporate proxy endpoint.

2. That particular proxy endpoint cannot establish a valid, trusted TLS connection to the API, due to one or more of the following:

* The proxy’s outbound connection to the API is blocked.
* The proxy performs SSL inspection and presents a replacement certificate that is not trusted by the SolarWinds Platform server.
* The ITSM endpoint certificate chain (or the proxy’s inspection CA) is incomplete or untrusted from the perspective of the proxy or the SolarWinds Platform server.

3. Because the proxy’s TLS negotiation fails or presents an untrusted certificate, every POST attempt from SolarWinds Platform results in:

* AuthenticationException errors.
* "The remote certificate is invalid according to the validation procedure."
* "Could not establish trust relationship for the SSL/TLS secure channel."

4. When the SolarWinds Platform is reconfigured to use a different outbound proxy endpoint that can complete a trusted TLS handshake with the API, the HTTP POST alert actions succeed.

To validate the issue, this is likely a TLS/proxy-related problem if the following conditions are met:

* Browser access from the SolarWinds Platform server to the API works successfully and shows a secure padlock, but
* PowerShell POST requests and SolarWinds Platform HTTP POST requests both fail with TLS/SSL trust errors.

In this scenario, please verify the following:

* Ensure the full certificate chain (including any proxy or SSL inspection CA certificates) is trusted on the SolarWinds Platform server.
* Confirm that the SolarWinds Platform is configured to use a proxy endpoint that can successfully establish a trusted HTTPS/TLS connection to the API. If the current proxy cannot complete a trusted connection, switch to one that can.