During the installation of the plugin have error

that’s strange. Can you switch on debug mode and see if you get any errors?

Now I have no any error with this plugin

Your forms translation relationships are not saved because Polylang has not registered the wpcf7 custom post for translation tracking. Please follow instruction #5 & #6 in the Installation section.

This was done primarily
https://joxi.ru/krDpBDvs078k1r?d=1

otherwise there would be no language settings for forms
https://joxi.ru/eAOq91wt4WN8dm?d=1

Try to install your plug-in to a clean version of WordPress and polylang.

The new release of Polylang broke something. THis is now fixed in the new release. Please update your plugin.