429 : "error": "Rate limit exceeded"

Hi,
We are running tyk environment which is running two instances one is http support and another one for https support. Each instance owning separate tyk.conf file but same redis server.
The issue is, external applications getting “429” “Rate limit exceeded” error.
The policy which created for the API’s is “no rate limiting”, policy conf sample,

{“vendorapp”:{
“quota_max”:-1,
“access_rights”:{
“1”:{
“api_name”:“service1”,
“api_id”:“1”,
“versions”:[
“Default”
],
“allowed_urls”:[

            ]
        },
    "hmac_enabled":false,
    "active":true,
    "is_inactive":false

}

JWT tokens were created based on policy name.
We don’t see any issues when we are running single http instance.
So Is the error because two instances?

Hi Team,
Is there any suggestion for this issue? Still im not able to get root cause for this problem.
appreciate your help.

Thanks