Need Help in ASRP UGC data migration from 6.1 to 6.3

I am upgrading my AEM instances from 6.1 to 6.3. I am facing some issue with AEM community feature in AEM 6.3 while it was working fine in 6.1. I am using ASRP method to store the data.

Below are issues on AEM community:-

1) Getting below 502 error frequently on community pages.

Cannot call AdobeSocial: Received 502 <html> <head><title>502 Bad Gateway</title></head> <body bgcolor="white"> <center><h1>502 Bad Gateway</h1></center> <hr><center>nginx/1.2.6</center> </body> </html>

2) On search old post with author name getting below 404 error.

org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Uncaught SlingException

java.lang.IllegalArgumentException: org.apache.sling.api.resource.PersistenceException: Cannot call Adobe Storage: Received 414 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">

<html><head>

<title>414 Request-URI Too Large</title>

</head><body>

<h1>Request-URI Too Large</h1>

<p>The requested URL's length exceeds the capacity

limit for this server.<br />

</p>

<hr>

<address>Apache/2.4.2 Server at socialdc1.omniture.com Port 80</address>

</body></html>

On further searching I got the below post to upgrade the community.

Upgrading to AEM 6.3 Communities

But the AEM communities utility configuration looks different in my AEM 6.3 instance. Highlighted field is not present in AEM 6.3.

Could you please help me how to resolve the above errors.