Appears (502 error) when a duplicate is found (Espo.ERROR: Display Error: )

[roman042]

Hello, appears (502 error) while finding a duplicate (Espo.ERROR: Display Error: ).

The rule for finding duplicates is this:

$data = array(
'firstName' => $entity->get('firstName'),
'lastName' => $entity->get('lastName'),
'middleName' => $entity->get('middleName')
);

Logs:
[2017-07-19 07:55:05] Espo.ERROR: Display Error: {"reason":"Duplicate","data":{"592c2f7d6c5d0d993": {"id":"592c2f7d6c5d0d993","name":"\u0420\u043e\u04 33\u043e\u0432\u0430\u044f \u0415\u043a\u0430\u0442\u0435\u0440\u0438\u043d\u 0430 \u0410\u043b\u0435\u043a\u0441\u0430\u043d\u0434\u 0440\u043e\u0432\u043d\u0430","deleted":false,"sal utationName":null,"firstName":"\u0415\u043a\u0430\ u0442\u0435\u0440\u0438\u043d\u0430","lastName":"\ u0420\u043e\u0433\u043e\u0432\u0430\u044f","middle Name":"\u0410\u043b\u0435\u043a\u0441\u0430\u043d\ u0434\u0440\u043e\u0432\u043d\u0430","accountId":" 592c0fb64d5cd6ba7","title":"\u0413\u043b\u0430\u04 32\u043d\u044b\u0439 \u0431\u0443\u0445\u0433\u0430\u043b\u0442\u0435\u 0440","description":null,"emailAddress":null,"phon eNumber":null,"doNotCall":false,"addressStreet":nu ll,"addressCity":null,"addressState":null,"address Country":null,"addressPostalCode":null,"accountTyp e":"","createdAt":"2017-05-29 14:26:05","modifiedAt":"2017-06-06 16:37:18","birthDate":null,"directumAnalit":"37970 9","gender":"Female","inn":null,"accountName":"\u0 421\u0442\u0435\u0440\u043b\u044f\u0433\u043e\u043 2\u0430 \u0422.\u0412., \u0418\u041f, \u0422\u043e\u0440\u0442\u0438\u043b\u0430","campa ignId":null,"createdById":"592bf7c6225f9c4db","cre atedByName":"\u0410\u0434\u043c\u0438\u043d\u0438\ u0441\u0442\u0440\u0430\u0442\u043e\u0440 CRM","modifiedById":"592bf7c6225f9c4db","modifiedB yName":"\u0410\u0434\u043c\u0438\u043d\u0438\u0441 \u0442\u0440\u0430\u0442\u043e\u0440 CRM","assignedUserId":null,"assignedUserName":null },"592c324c24c1372a6":{"id":"592c324c24c1372a6","n ame":"\u0420\u043e\u0433\u043e\u0432\u0430\u044f \u0415\u043a\u0430\u0442\u0435\u0440\u0438\u043d\u 0430 \u0410\u043b\u0435\u043a\u0441\u0430\u043d\u0434\u 0440\u043e\u0432\u043d\u0430","deleted":false,"sal utationName":null,"firstName":"\u0415\u043a\u0430\ u0442\u0435\u0440\u0438\u043d\u0430","lastName":"\ u0420\u043e\u0433\u043e\u0432\u0430\u044f","middle Name":"\u0410\u043b\u0435\u043a\u0441\u0430\u043d\ u0434\u0440\u043e\u0432\u043d\u0430","accountId":" 592c022912646b784","title":"\u0414\u0438\u0440\u04 35\u043a\u0442\u043e\u0440","description":null,"em ailAddress":null,"phoneNumber":"83422181700","doNo tCall":false,"addressStreet":null,"addressCity":nu ll,"addressState":null,"addressCountry":null,"addr essPostalCode":null,"accountType":"","createdAt":" 2017-05-29 14:38:04","modifiedAt":"2017-06-06 20:17:12","birthDate":null,"directumAnalit":"27192 97","gender":"Female","inn":null,"accountName":"\u 041f\u0413\u0421 \u0413\u041f, \u041e\u041e\u041e","campaignId":null,"createdById ":"592bf7c6225f9c4db","createdByName":"\u0410\u043 4\u043c\u0438\u043d\u0438\u0441\u0442\u0440\u0430\ u0442\u043e\u0440 CRM","modifiedById":"592bf7c6225f9c4db","modifiedB yName":"\u0410\u0434\u043c\u0438\u043d\u0438\u0441 \u0442\u0440\u0430\u0442\u043e\u0440 CRM","assignedUserId":null,"assignedUserName":null },"592c4282084a2c1ec":{"id":"592c4282084a2c1ec","n ame":"\u0420\u043e\u0433\u043e\u0432\u0430\u044f \u0415\u043a\u0430\u0442\u0435\u0440\u0438\u043d\u 0430 \u0410\u043b\u0435\u043a\u0441\u0430\u043d\u0434\u 0440\u043e\u0432\u043d\u0430","deleted":false,"sal utationName":null,"firstName":"\u0415\u043a\u0430\ u0442\u0435\u0440\u0438\u043d\u0430","lastName":"\ u0420\u043e\u0433\u043e\u0432\u0430\u044f","middle Name":"\u0410\u043b\u0435\u043a\u0441\u0430\u043d\ u0434\u0440\u043e\u0432\u043d\u0430","accountId":" 592c01156ece5ee2f","title":"\u0414\u0438\u0440\u04 35\u043a\u0442\u043e\u0440","description":null,"em ailAddress":null,"phoneNumber":"83422181700","doNo tCall":false,"addressStreet":null,"addressCity":nu ll,"addressState":null,"addressCountry":null,"addr essPostalCode":null,"accountType":"","createdAt":" 2017-05-29 15:47:14","modifiedAt":"2017-06-07 06:02:23","birthDate":null,"directumAnalit":"27222 01","gender":"Female","inn":null,"accountName":"\u 041f\u0413\u0421 \u041e\u041f\u0422\u041e\u041c, \u041e\u041e\u041e","campaignId":null,"createdById ":"592bf7c6225f9c4db","createdByName":"\u0410\u043 4\u043c\u0438\u043d\u0438\u0441\u0442\u0440\u0430\ u0442\u043e\u0440 CRM","modifiedById":"592bf7c6225f9c4db","modifiedB yName":"\u0410\u0434\u043c\u0438\u043d\u0438\u0441 \u0442\u0440\u0430\u0442\u043e\u0440 CRM","assignedUserId":null,"assignedUserName":null }}}, Code: 409 URL: /api/v1/Contact [] []

[roman042]

The reason was in Nginx : "upstream sent too big header while reading response header from upstream"

Adjusted settings all became good:
/etc/nginx/nginx.conf

proxy_buffers 16 128k;
proxy_busy_buffers_size 128k;
proxy_buffer_size 128k;