Since the release of the Endwalker expansion, many players have struggled to get on a server to play the mmo. This is due to the large amount of players.
Director Naoki Yoshida has apologized in a blogpost and reported that anyone who has the game and a subscription will receive seven days of free playtime. Players who have a 30-day free trial who signed up for the full version of the game will also receive these 7 free days.
The blog post also mentions the busiest times of the day, so that players can take this into account if necessary. Endwalker officially releases tomorrow, but went into Early Access last Friday.