You once fat-fingered your login name to a web site and now Firefox suggests the typo every single time in the auto-complete dropdown. So annoying! But the Captain's Universe web site has a quick tip on how to delete the bad suggestions:
Mozilla defines a special JavaScript object to allow web pages access to certain cryptographic-related services. These services are a balance between the functionality web pages need and the requirement to protect users from malicious web sites. Most of these services are available via the DOM window object as window.crypto.
about:config über die Adresszeile aufrufen, connections als Filter eingeben und die Werte für network.http.max-connections network.http.max-connections-per-server network.http.max-persistent-connections-per-proxy network.http.max-persistent-connections-per-server erhöhen.