# Connection Errors
Below are a list of all known possible connection errors and examples of stack traces with those errors.

## AgentVEP errors

### invalid url received from app server

Accounts that get this error seem to be unable to recover from them.

**Cause:** Unknown

```
VError: Error while getting auth token from AgentVEP
LeLogin1 failed - invalid url received from app server: Request failed with status code 500
at Object.getAgentSession (/liveperson/code/lp-controller-bot/node_modules/lp-messaging-sdk/lib/services/agentVep.js:84:15)
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
at async BrandWebsocketConnection._generateToken (/liveperson/code/lp-controller-bot/node_modules/lp-messaging-sdk/lib/connection/connection-websocket-brand.js:108:32)
at async BrandWebsocketConnection.connect (/liveperson/code/lp-controller-bot/node_modules/lp-messaging-sdk/lib/connection/connection-websocket-brand.js:46:13)
```