token disappeared from char and, when reloaded, can't be dragged

I have a character that has always had the same token image.  However, when prepping for a game on Thursday (as a player), I noticed that my avatar had been replaced with the "error" image (typically file not found image).  Even stranger, the avatar and token had also disappeared (file not found image again) from the character sheet in my character vault. I was able to edit the character sheet in the game and reload the avatar image.  However, neither the GM nor myself can drag the token onto the map now (neither from the bio page of the char sheet nor by dragging the char name from the journal). It's going to be hard to play without a token.  Does anyone have any ideas (on why it disappeared in the first place or why reloading it doesn't fix the issue)?

Update.  I have no idea why the token image disappeared in the first place but I think I know what the can not drag issue is (but not how to fix it).  After reuploading the avatar image on the char sheet and importing the char to my char vault, the avatar image is corrected but the default token image is still the "missing" indicator (so it is likely dragging nothing to the map).  How can I get the default token image to match the avatar image?

What happens when you try to create a new default token? I.e., what is the step-by-step procedure you are following? If things are not done in the proper order, the default token may not get set correctly or at all.

The difficulty is that I'm a player in the game (so can't set default token even for my own char sheet as far as I can tell) and that I'm a free user (so can't just export the char into a new game I create and then import back to the char vault).

Tangential question - why can a player NOT set their own default token?  This is not the first time where I've run into an issue of avatar vs default token (last time it was diff images so my avatar looked like I wanted but the default token was set to something else so, when I dragged it, I got the "wrong" image for the token).

The avatar and the token do not have to be the same (they virtually never are for my characters). The GM is the one who sets default tokens for their campaign. Not sure exactly why, but it likely has something to do with the GM controlling the aesthetic of their game, ensuring all top-down or all portrait tokens, for example, or maybe preventing "inappropriate" tokens. I would guess that there is likely a suggestion in the suggestions forum to add this ability, if you want to track it down and you have a free vote.

I've had several tokens disappear from characters as well (in a game I GM).  Virtually no chance a player did this somehow, and I certainly didn't.