In The First Descendant, a small error can currently delete all of your progress. But you can easily prevent that.
How is your progress deleted? As some players report on Reddit and the official Discord server of The First Descendant, you can lose your progress if you decide to link your account to a Nexon account afterwards.
You will then see the progress of the Nexon account, which has been unused until now and has no progress.
How can you protect yourself? You should currently refrain from linking your account to a Nexon account. This is the only way to ensure that you do not lose your progress.
If you link your account to a Nexon account directly at the start of the game and have only gained progress afterwards, your progress is safe.
What to do if the progress is gone? You can unlink your account from your Nexon account. This should cause your progress to return – at least according to the reports of some players.
Has Nexon commented on the issue? No, we currently do not have a statement from Nexon regarding the issue. However, since the developers have reacted attentively to feedback from the community so far, and they actively share the issue on Reddit and Discord, it is quite possible that the developers will respond.
Many players can probably do without the linking right now. However, it is annoying if you have started playing on one platform and now want to continue on another. The First Descendant offers cross-progression, but this is only possible with a Nexon account. You can read more about cross-progression and crossplay on MeinMMO: The First Descendant: Crossplay – Can PlayStation, Xbox, and PC play together?