As reported by ALLKPOP, an announcement from the event management Dream Maker Ent. Limited stated that Lay will not be participating in the remaining of the EXO concerts.
This is their official announcement-
“Lay will not be able to attend the oversea tour scheduled in the future due to his failure in schedule adjustment. It’s unfortunate that we have to deliver such news to everyone who’s looking forward to Lay’s attendance at Kuala Lumpur, Singapore, and North America. The remaining tour will be completed with the 8 members without Lay.”