My disc lost connections after NAS installation zyxel 542

Ive installed 4*4TB and Raid 5 (was suggested) and it worked perfect until restart
then my Zyxel lost all discs.
-Already installed latest upgraded firmware Zyxel NAS542
-Try pull out one disc and the system repaired 1disc and continued beeping
-How to fix this easy with current installation have Seagate Ironwolf4TB discs
-Or can i go back to square one have re-install raid on all the discs
What to do?

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