When I try to load a particular website from my company it suddenly won't open and I get an error message. Even though it has worked perfectly every day for the 的最新解答https://support.mozilla.org/zh-TW/questions/12822382020-03-17T06:17:20-07:00Hi jrebelojr65, this error message refers to the level of TLS protocol used by the site: TLS 1.0, TL2020-03-17T06:17:20-07:00jscher2000https://support.mozilla.org/zh-TW/questions/1282238#answer-1298353<p>Hi jrebelojr65, this error message refers to the level of TLS protocol used by the site: TLS 1.0, TLS 1.1, TLS 1.2, or TLS 1.3.
</p><p>Recently Firefox is retiring TLS 1.0 and 1.1, but possibly your work site still uses the older version? You could take a look at the following settings:
</p><p>(1) In a new tab, type or paste <strong>about:config</strong> in the address bar and press Enter/Return. Click the button accepting the risk.
</p><p>(2) In the search box above the list, type or paste <strong>TLS</strong> and pause while the list is filtered
</p><p>(3) Double-click the <strong>security.tls.version.enable-deprecated</strong> preference to switch the value from false to true
</p><p>(4) If the <strong>security.tls.version.max</strong> preference is bolded and has a value less than <strong>4</strong>, reset to the default value by clicking the button toward the right end of the row with the left-pointing arrow
</p><p>When you visit the site again, does Firefox let you access it now, either using the latest TLS or by downgrading to an older version of TLS?
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