A player must be on the Allowed Playerlist (APL) before being allowed to play a match. That means, a player must be added to your clan roster as well as to the APL before the official starting time, the scheduled start time of the match shown on the wid page.
You can bet at war time @ 21:30, player in question Lowe aka Dekadance was not on apl
Yellow card for expendables for playing with an irregular player. Next time (and this is for all clans) add your players 24 hours to your clan roster so you will avoid problems. Results stays as 24-24 so add screenshots for a match report.