web-server ubuntu 16.04
PHP 7.0.8
Apache/2.4.18

Client ubuntu 16.04
Browsers -Chromium 52

Could you please elaborate a bit on the necessary steps to reproduce the error?

Create new map -> added two elements -> added link between the elements and click update map.
From the error text it is seen that the link id already exists in the database. What can be done to zabiks indexed base for free link id?

ps Sorry for my english

Tried with both PHP 5.6.24 and PHP 7.0.8, but the issue did not manifest. Can you reproduce the problem on a fresh database (e.g., by creating a fresh installation, importing some hosts and maps required, and then trying the described scenario)?

There are new details. The base change was made manually via mysql two hosts are added, and the link between them. As I understand zabbix "thinks" that there is no such link and adding a link via a web interface receives an error.

sounds like no bug in zabbix then - your direct database modifications apparently have been incorrect

Hosts and links that have been made by changing base, on the map displayed correctly. There is no test available in zabbix free checking id link there or not? Where from takes information about id link when creates a new link?

please see http://zabbix.org/wiki/Getting_help for support options.

in this specific case, you might have forgotten to update the 'ids' table

Ок, thanks for the help.

It is necessary to update zabbix.ids

Reopening to set the correct resolution...

Closing as "Won't fix" as per richlv's comments above.