No verification methods are enabled in Affiliation Settings
Webmaster site verification threw because Affiliation Settings have no verification methods turned on.
Why this happens
Admin disabled all methods (DNS, meta tag, etc.). Members cannot prove ownership until at least one is enabled. Related short form may omit “in Affiliation Settings”.
Diagnose and fix
1. Admin → Affiliation Settings — enable DNS and/or meta tag verification (as offered).
2. Save; member retries verify on the site.
3. See Website DNS verification and Website meta tag verification.
4. See Webmaster sites and verification.