Open API 2.0: Can authorize multi accounts at the same time?

Dear all,

I am developing an HTTP service using Open API 2.0.

The service serves as a trade terminal endpoint (https://api.mysite.com/ctrader/trade) which trader can send a trade command to execute. Traders registering their account with accountId and access_token to able to execute the commands.

The command send to this endpoint via http POST, the service will connect to Ctrader accounts and trade as trader commands.

Everything work well with single account. If multi traders send multi commands to multi accounts, the API return error. The 1st account was Authorize successful but the next one raise error:

Error:  ctidTraderAccountId: xxxxx
errorCode: "CANT_ROUTE_REQUEST"
description: "No environment connection"

Is this error said that I cannot connect multi accounts the same time? 

Regards,

URI.