We definitely want to get to the bottom of this! Could you please get in touch with the support team (you can do so via support@mailerlite.com). This way they can search into your account, follow the issue and try to find a solution with you.
Here is the answer from your techs:
They are great people and tried to help but to no avail:
Hey Yuriy!
The integration should be working now. Our specialists have made a few test orders and the email was successfully synced both times and custom field data was populated. However, the abandoned cart doesn’t seem to be working because a plugin is interfering with the behavior. I wasn’t able to see abandoned carts in WooCommerce either so it’s possible that they are not being tracked by WooCommerce itself. If that’s the case, this would be the issue for the MailerLite plugin as well.
However, purchases can be made and the information is immediately sent to MailerLite.
Thank you so much for your patience in this matter, Yuriy, I greatly appreciate it.
I’m not on my shift today, but I wanted to share with you the update. If you have any further questions about this feel free to answer me here but I’ll be back on Monday, so please open a new chat and a colleague will immediately help.
Meanwhile, I hope you have a great weekend 🙏`