Good morning! Thank you for posting in the Final Fantasy XIV Technical Support Forums.

We apologize for any inconvenience experienced when trying to play Final Fantasy XIV. Please try the following troubleshooting suggestions:

Open the control panel of the PC and go to ‘Network and Internet’. Once there select ‘Internet Options’
- Under the "General" tab, please delete ALL browser history.
- Under the "Security" tab, please move the slider to the lowest possible settings or no higher than "Medium"
- Under the "Privacy" tab, click “Advanced” and select ‘Accept’ under both First Party and Third Party Cookies.
- Under the "Advanced" tab, please make sure that "Allow software to run or install even if signature is invalid" is CHECKED.
- Make sure that all SSL and TLS (EXCEPT SSL 3.0) are CHECKED. [SSL 3.0 should be UNCHECKED]
- Hit "Apply" to save the settings, and then "OK, to close the Internet Options menu.
- Right-Click on the FFXIV launcher icon and select "Properties"
- Hit "Apply", then "OK" to save the changes.
- Please RESTART your PC now. Once your PC has been restarted, Right-Click the FFXIV launcher icon once more and select "Run as Administrator"
*Make sure your fire wall or antivirus program is not interfering with the game.

- Try disabling background applications and do a clean boot by opening the task manager and selecting the “Start up” tab. Disable everything and then restart the PC.
- We suggest to power cycle the device and router by shutting down the Router and leaving the power supply unplugged for 30 mins. to an hour.
 
- Flush DNS: Within the "Command Prompt" of the device, please type the command "ipconfig /flushdns".
- Reset TCP/IP: Also within the Command Prompt, type the command "netsh int ip reset" and then restart the computer.
- Change local DNS: Please try changing the local DNS server to 8.8.8.8 and 8.8.4.4
- Lastly, after changing the DNS settings, please try switching Data Centers once more then switch back to your original Data Center.

For the version check/update error, please try the below:
- Delete the Patch Folder: Navigate to the folder using this path: This PC > Docs > My Games> FFXIV ARR > Downloads > FFXIV patch
Then either rename or remove the folder, the next time FINAL FANTASY XIV is launched, the client will repair the folder.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV.