Seems the discussions endpoint is broken:
PDOException: SQLSTATE[42000]: Syntax error or access violation: 1104 The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay in /customers/f/d/9/openstudio.one/httpd.www/community/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php:117\nStack trace:\n#0 /customers/f/d/9/openstudio.one/httpd.www/community/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php(117): PDOStatement->execute(NULL)\n#1 /customers/f/d/9/openstudio.one/httpd.www/community/vendor/illuminate/database/Connection.php(373): Doctrine\\DBAL\\Driver\\PDOStatement->execute()\n#2 /customers/f/d/9/openstudio.one/httpd.www/community/vendor/illuminate/database/Connection.php(705): Illuminate\\Database\\Connection->Illuminate\\Database\\{closure}('select * from `...', Array)\n#3 /customers/f/d/9/openstudio.one/httpd.www/community/vendor/illuminate/database/Connection.php(672): Illuminate\\Database\\Connection->runQueryCallback('select * from `...', Array, Object(Closure))\n#4 /customers/f/d/9/openstudio.one/httpd.www/community/vendor/illuminate/database/Connection.php(376): Illuminate\\Database\\Connection->run('select * from `...',
I've not seen this before, perhaps your MySQL is limiting the number of joins? Is this shared hosting, can you get support on the server from your end?