Player not showing up (and has logged into the campaign)

I can't assign this person a character sheet. And they have logged into the campaign, which is the usual answer in this forum. Help please! (Five other players have logged in and are able to get assigned a sheet.)

First sanity check: are you sure you are checking the correct game? (Sometimes GMs will copy a game, and a player is active in the original but not the copy, etc.) If so, do you see them on the Game Page in the invited players section? If not, then they either accidentally left the game, or got booted somehow and need to be reinvited.  Make sure to send them a new game link. If so, do you see them on the 'Edit and Control' dropdown for a character? If they are listed as an active/invited player, but are not showing up in the 'Edit and Control' dropdown, then try booting them from the game and reinviting them, as that's possibly just a bug.  If that still doesn't work, then something else is going on.  Try loading the game in an incognito browser just to make sure there's not an extension interfering.  If that still doesn't work then you'll likely have to submit a Help Center request .

Make sure they have ENTERED  the game. Being listed is not enough, that is the website side. They have to enter the game to be registered in the VTT side of the game.  (I know you have said they logged in, just double checking.)

Another possibility: Make sure their player/user name does not have any control characters in it— quotes, brackets, parentheses, symbols that are used in macros... Also, that it does not begin with a space (which might throw it out of order). Finally, make sure that their  player/user name does not duplicate a monster. I.e. they are not named "goblin" if there is a "goblin" NPC. These are all stretching the bounds of likelihood, but without more info, we can only supply guesses.

Thanks all who offered advice! I booted him and re-invited, and here's what he thinks happened: Sorry looking at this now (just logged off of work 😅) Okay so weird, check now. I noticed it lets me "enter" the game when I click the link in the email, but then in my messages there was one that said "Accept Invite" which I had to click (but it let me enter the game without clicking it) Maybe the game was set to public or something so I could enter the game with just the link from the email, but I had to actually accept from the internal roll20 mail