Here to BUMP this post.

I have friends and some family who have this exact same issue with the same network down to every detail provided by OP. Only way for them to get around this error 2002 was to try and see if connecting their phone and sharing internet through it works (which it did.)

I have never had any issues regarding this error and I have different ISP. Therefore their problem seems to be localized between Kyläverkko - yok.fi /FUNET CSC and whatever servers this Data Center connection happens. It does NOT matter if you change Data Center from EU to NA to JP. My friend played last year and earlier this year with no issues and noticed this problem on 15th of March, the day he resubbed back to FF14.

I do not think it acceptable that using phone internet/VPN/Cloudware or other 3rd party programs would be requirement to play the game due to this particular issue.