As noted at T277987#7012017, Special:Mute lumps three different error messages together, making it hard to distinguish between them.

"specialmute-error-no-options": "Mute features are unavailable. This might be because: you haven't confirmed your email address or the wiki administrator has disabled email features and/or email blacklist for this wiki."

For example, if email is disabled globally on the wiki, it doesn't matter that your email hasn't been confirmed, because you can't enable it.

It seems worthwhile splitting this message down into 3 or 4 different messages, and displaying a "Header" error, along with the individual errors underneath.

Further improvements could be also applying some logic as to which errors are shown dependent on the others. Though, I admit the "fix one error and get a different error message" workflow can be annoying, so maybe there's not much benefit doing that part of the work