His label posted on the boys' official fancafe, 

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Hello, this is Fantagio.

ASTRO's Cha Eun Woo suddenly came down with cold symptoms, so he will not be attending any of the schedules today and will be resting.

After ASTRO's concert in Taiwan yesterday, his condition dropped and he had symptoms of a cold, so we took him immediately to the hospital for treatment. He has gotten much better now, but doctors told him that it would be better for him to rest at least one more day for him to focus on recovery, so he will not be attending any of ASTRO's schedules today. We apologize once again to the Taiwanese fans who have been waiting for ASTRO. 

We are telling you this because AROHA will be worried about Cha Eun Woo's health. We apologize for worrying fans, and we will do our best so he can focus on recovery and join in the rest of the schedules.

Thank you.

Hopefully he gets better soon!