Check your site is not listed on any security blacklists

Security blacklists (like Google Safe Browsing or major spam/malware block lists) flag sites that have been compromised or are distributing malware — being listed, even by mistake, can trigger browser warnings for every visitor or get your emails blocked outright.

A blacklisting event can happen even to a legitimate site that was briefly compromised, and it is worth actively checking rather than only discovering it when a visitor reports seeing a warning.

How to do it

1. 1
   Check major blacklist services directly

   Google Safe Browsing, and general blacklist aggregator tools that check dozens of lists at once.
2. 2
   If listed, identify and fix the actual root cause first

   Blacklisting almost always means something genuinely was compromised or misconfigured — fix that before requesting removal.
3. 3
   Request delisting through the proper process

   Each blacklist has its own request process, typically through Google Search Console for Safe Browsing specifically.
4. 4
   Re-check periodically

   A quick recurring check catches a future listing early rather than after visitors start reporting warnings.