Mac client is 32-bit

Date & Time: Always
Frequency: Always
World name: N/A
Character name: N/A
Retainer name: N/A
NPC name: N/A
Monster name: N/A
Class/Level: N/A
Party or solo: N/A
In-game time: N/A
Area and coordinates: N/A
Housing: N/A
Steps:
1. Apple Menu > About This Mac > System Report... > Applications
2. Notice the FINAL FANTASY XIV application is not 64-bit
3. Launch the FINAL FANTASY XIV, sign in and launch the game
4. Open the Activity Monitor of macOS, add the Kind column
5. Notice the game is in 32 bit

Connection Specs
- Type of internet connection/provider: N/A
- Modem maker/model number: N/A

macOS 10.13.x (High Sierra) is the last version of macOS to support fully 32 bit applications. Starting with 10.13.4 beta, users get a notification about 32 bit apps.

https://arstechnica.com/gadgets/2018...t-app-support/

Please make FINAL FANTASY XIV launcher and game for macOS 64-bit before the fall release of macOS 10.14