To expand on @cubansyrus 's comment, here it is directly in the rules:
11. Users are prohibited to use any kind of the software which allows you to open several client windows simultaneously, i.e. playing several characters at once - such behavior would result in account block without any possibility to revoke it.
You can have all the alts you want on a single account but you may only have 1 account per person. Accounts proven to be feeding all the gold and resources to another account may also be monitored and dealt with.
Personally I think this is great. Managing multiple accounts on Official servers is a huge reason of why I kept burning out on the game. Official NA AA has jokingly been called AltAge but its rather true. The game was designed to be 1 person per account and I believe a lot of the issues we had native to NA version stemmed from the benefits of individuals multiboxing trade runs and a single person having 10x the best reward in an event because they had 9 other accounts. Trion allowed it because each one is another $15 per month if you pay for them directly or $20 if someone bought the Apex and you use those to renew patron. All these alts trying to renew patron F2P was also the biggest reason for its inflation each month. On this server the main reasons we had any inflation to credit packs at all was the week and a half we went with the donation system down and now where only crypto currencies are accepted.
After playing this server, Im convinced that 1 account per player is absolutely the right choice for an AA server. I have no desire whatsoever to play on a server that allows multiple accounts or multi-boxing again.