For the last few days I have been receiving the same error but with different codes when trying to launch FFXIV from steam.

"FFXIV Boot Error
Unable to complete version check.
30605 10009 19900 12030"

At this point I have gotten multiple error codes including
30605 20448 10009 10019 and 30605 10009 19900 12029

At first I thought it was my connection, but I am able to play any other game just fine. Another issue i have found is that FFXIV seemed to randomly work in the mornings but not the evenings. Now it doesn't seem to work at all or very sporadically. I have tried everything I could think of and find online when googling this issue. But it persists and I'm getting a little frustrated because there seems to be no logic behind it. At this point I'm suspecting it may have something to do with my provider and their connection to ffxiv servers? I'm not the most tech savvy so please excuse me. But I have no other explanation for it considering that i have installed it on another device and I can not get into the launcher either. Though there it tells me to make sure the game isn't under maintenance and to check my connection rather than just an error code.
If anyone has any suggestions of what might be causing this or fixes, I would be thankful. Though I can not guarantee that I haven't tried it already.