Steps to reproduce the issue

Install Disqus plugin and add some new tags in Joomla articles.

Expected result

When reading content on website, click on any Joomla tag and list the articles containing those tags (Normal Joomla behavior,as it should be)

Actual result

When reading articles on your website and click on any tag (previously created in articles) you get the following error: 'This page isn’t working
-Your site name here- is currently unable to handle this request.
HTTP ERROR 500'
The error message appear in Google Chrome. In Mozilla Firefox you get a blank page instead of the error message.

System information (as much as possible)

System Information
Setting Value

PHP Built On Linux cloud416.mxserver.ro 3.10.0 #1 SMP Fri Jan 5 21:20:16 MSK 2018 x86_64
Database Type mysql
Database Version 5.5.5-10.2.14-MariaDB
Database Collation latin1_swedish_ci
Database Connection Collation utf8mb4_general_ci
PHP Version 5.6.36
Web Server LiteSpeed
WebServer to PHP Interface litespeed
Joomla! Version Joomla! 3.8.7 Stable [ Amani ] 18-April-2018 14:00 GMT
Joomla! Platform Version Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36

Additional comments

The mentioned issue is resolved by disabling System-Custom Fields plugin. Any other solution known? Thank you !