I had a similar issue.  I just found out how to fix it.  Here is what you do:

The manager will need to go to the Edit Team Settings option for each team they have and select the option to allow others to see their email, and Submit the change.

I searched forever on how to fix that.  If that doesn't work you have to go to your Yahoo Profile and make changes as well.  Hope that helps.

  

Also get the following when trying to edit profile:

Sorry, server error. Please check the URL for proper spelling and capitalization. If you're having trouble locating a destination on Yahoo!, try visiting the Yahoo! home page or look through a list of Yahoo!'s online services. Also, you may find what you're looking for if you try searching below.

Allow others in league to see my email address?

I click "yes" and SAVE, but when I check it again, it's reverted back to "no."

  

 Have the exact same issue. No clue as to how to fix it. 

  

 I have the same issue. I had went to my profile and changed my Nickname from "Commissioner Goodell" and saved it as blank. After that, I couldn't acess my profile page, my Nickname can't be changed, my Avatar Photo can't be changed, and my name on the "Manager" section of Fantasy Football appears as "--hidden--". There is no way to change it to be unhiden that I have found yet. And I know it's not a server issue, because I can access the profile and all the settings on another Yahoo name I have. Something tripped out Yahoo on this name. And why can't they fix it? It's ruining the Fantasy Football experience. 

  

 Great, I'm having the same exact issue and was hoping there was an answer here. Just going to the upper left, clicking my name and then "Profile" I get an error:  Sorry, server error.

I can't upload a new picture in fantasy football either because the page errors out. It's like I have NO access to my profile.