I don't have access to real-time events or specific details about the 2017 Mnet Asian Music Awards (MAMA) or any events that occurred after that date.
However, I can provide some general information about EXO and their connection with MAMA. EXO is a popular South Korean-Chinese boy group formed by SM Entertainment. MAMA is an annual awards ceremony hosted by Mnet, a South Korean entertainment channel, to honor outstanding achievements in the Asian music industry.
EXO has had a special relationship with MAMA since their debut. They are known for their powerful performances, memorable stages, and numerous awards they have won at the event over the years. MAMA has been a platform where EXO showcased their talent and received recognition for their musical contributions, which has led to emotional moments on stage, including tears of joy and gratitude.
As for any specific incident in 2017 or any other year, you may need to refer to reliable news sources or fan accounts for more detailed information on why EXO members cried during that particular MAMA ceremony. Keep in mind that artists' emotions can vary based on the significance of the event, personal experiences, and various other factors.