By Katie Wilson Adele has failed to sell out her European comeback tour as fans fear she may pull out of gigs at the last minute. Tickets for her 10-date Adele In Munich gigs went on sale two weeks ago and apparently extra dates were added “due to unprecedented demand”. Yet thousands of tickets remain available for the dates listed on Ticketmaster from August 2 to August 31. It comes after Adele was forced to pull out of some of her Las Vegas residency gigs, which were due to take place this month. Apologising for the ‘inconvenience’ in a statement on Instagram on February 28, the 35-year-old …