Your name appears in https://signatures.toolforge.org/reports/www.mediawiki.org as having an invalid custom signature. There is more information about this at New requirements for user signatures/Help. I think the main problem is that your custom signature does not link to any page about you (User:Vedmaka, this page, or Special:Contributions/Vedmaka – only one link is necessary). You can update your custom signature in Special:Preferences whenever it's convenient.