You cannot receive transfers from other PayPal account holders.

[infosite]

Hello. Help me resolve the issue, they are trying to send me a payment, but it is rejected, what could be the reason? Registered since 2015. And how to write to support?

[kernowlass]

@infosite 

Paypal account holders in the Ukraine can now receive payments with the recent change of policy, but they are restricted to receiving only friends/family payments as per link.
https://www.paypal.com/ua/smarthelp/article/faq4646

However the friends/family option is not available in every country.
The sender may be in one of those countries so would not be able to send friends/family payments to the Ukraine OR they are trying to send you goods/services payments which is not allowed as you still can't do commercial transactions and receive goods/services payments.