Start by identifying the failing stage: adding the connection, discovering tools, running one tool or verifying a write. Capture the time and a short description before changing settings.
Connection cannot be reached#
Check the exact assigned endpoint and whether the AI client supports its transport and authentication method. A platform home address is not an MCP endpoint. Use the normal secure connection; do not bypass a certificate warning.
If the same assigned connection previously worked, report when it last succeeded and what changed in the client. Avoid deleting working connection details before a replacement is verified.
Error reference#
| Symptom | What to check |
|---|---|
401 at connection or discovery | Missing, wrong, expired or revoked credential; incorrect header or endpoint. |
403 for an operation | Credential scope, tool permission or upstream service role; identify which layer returned it. |
429 | Request allowance exceeded; respect the retry delay and reduce request frequency. |
404 | Endpoint or referenced record may be wrong or unavailable; check the exact path and context. |
5xx or unavailable | Platform or upstream service issue; capture time and request stage. |
| Invalid arguments | Required field, input type, unsupported extra field or a mismatched identifier. |
| Connected but no expected tool | Assigned scope, inactive or unverified addition, or stale client discovery. |
| Tools appear but calls fail | Upstream authorisation, account entitlement or operation-specific input. |
These are diagnostic starting points. The actual source of an HTTP error matters; a service's permission error is not fixed by weakening MCP authentication.
A safe diagnostic sequence#
Confirm the endpoint, refresh the tool list, compare it with the handoff and run the agreed read-only test. If it fails, record the tool name and redacted error. Stop before repeating a write action whose result is uncertain.
What to send support#
Use the support checklist. Include a redacted screenshot or the relevant error text, not a full conversation export or a configuration containing a key.