South East Asian and Taiwanese Phantasy Star Online 2 Servers Announces Service Closure. SEA server will be closed on on May 26th and TW server later this Month.
Phantasy Star Online 2 - SEA and TW Servers Announces Service Closure
If you miss Phantasy Star Online 2, you can still play on Japanese servers. Registration will be similar to Closers Online, just you need to select PSO 2.

SEA Server Service Closure Information
Phantasy Star Online 2 - SEA and TW