@matos100 this is really bad advice, setting ARMING_CHECK to 0 turns off all the automated sanity checks for making sure that you are actually ready to fly and can lead to taking off with a system that knows its unhealthy but it isn’t clear to the user.
@aamadeuss I assume you have ARMING_RUDDER set to 1 or 2? If so I’m afraid I haven’t ever used the feature but @tridge or @magicrub might be able to help you more.
This is your problem that you need to figure out, don’t do any unwise workarounds. Rudder arming > 0 as @wickedShell said and check yaw ranges: it needs to detect a 90 or 95% yaw input. Check your trims and ensure yaw is connected.
In your transmeter go to the page where you set the stick range for the chanels like the Ail Thr Elev and make shure your Rud or yaw is 100 or -100 or the similer in in your case as your plane has a V tail.