@Reynaud you have not said which firmware version you are using, but in any case always start troubleshooting of this type with the latest firmware version that is available....

@CeApollo Oh, so you need DNS Suffix in the wireguard tunnel, put this in your wireguard file DNS = 192.168.5.2, customized.local.domain

@CeApollo no vpn interface ip should not overlap with any lan ip, do you get pinged anything at all? can you get the ping from 1.1.1.1

@CeApollo you must not use the same ip in the vpn tunnel as you have on the lan they must not overlap. also don't use /24 network in vpn, use /32 on server and client, /32 on each peer with unique ip...

@ravipati450 there is no problem to use one controller for multiple sites, but you should use OC300 or OC400 , OC200 is quite weak, I wouldn't use it on a single site even once.

@sadaman Go to switch port settings.