How to send messages using the Email Marketing module in Bitrix?

Question

1C-Bitrix

I'm trying to make an email campaign using the Email Marketing module, but instead of sending messages, the status "Segment is being prepared" is displayed endlessly and messages are not sent. There are no problems with sending messages, because the test letter arrives correctly and immediately. I use the trial version of Bitrix "Small Business", version 21.400.100.