Custom fields not importing

Hi,
We are displaying events on website (A) with 3 custom metabox fields (‘coupon’,’event_link’,’register_link’) and it is working fine. While we import events on our website (B) we loss those custom fields.

Both of our sites have using “all-in-one event calendar”, recent wordpress, metabox plugin & created 3 custom fields. Is there any way we can import custom fields to website (B) or if not what should we customize to get it working?

Sorry, i can’t share website url due to privacy.

Thanks

https://www.ads-software.com/plugins/all-in-one-event-calendar/