cURL error on activation

Hi,
I am trying to activate your plugin on a website https://citymoms.ru/.

It keeps giving me a ‘cURL library needed’ error, even after the library was installed.

I first installed the recommended version of the library and then tried to use higher version as well – with no success.

I also tried to deactivate all the plugins on the site in case there was a conflict, but that didn’t help either.

Deactivating current theme and activating Twenty Seventeen theme didn’t help, too.

Could you please give an advice what else might cause the problem and where to look?

Thanks heaps,

Maria