Willie Nelson has canceled his tour due to breathing problems, the musician announced on Twitter. Nelson was currently touring the U.S. and had just finished a show in Toledo, Ohio.

"To my fans, I'm sorry to cancel my tour, but I have a breathing problem that I need to have my doctor check out," he wrote. "I'll be back Love, Willie." He was on the road with country singer Alison Krauss. 

Nelson is set to headline his Farm Aid festival in Wisconsin on September 21. The music festival raises money to help farmers fight to stay on their land. The 86-year-old will resume touring in September and perform at the festival, according to Rolling Stone. 

This is not the first time Nelson suffered from breathing problems. He canceled a series of shows last year after suffering from a bad cold, and was also hospitalized in 2012 for respiratory issues, Entertainment Tonight reports.