Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

from [/questions/1338593#answer-1417523] ''<p>AliceWyman said</p>'' <blockquote>FTP support was disabled in Firefox 88 for security reasons, according to the release notes: https://www.mozilla.org/firefox/88.0/releasenotes/ (For more information, see [https://bugzilla.mozilla.org/show_bug.cgi?id=1691890 bug 1691890] and [https://bugzilla.mozilla.org/show_bug.cgi?id=1574475 bug 1574475].) As a temporary workaround, you can set the '''network.ftp.enabled''' preference to '''true''' in about:config until FTP support is removed, which is planned for Firefox 90. </blockquote> . . Also https://blog.mozilla.org/addons/2020/04/13/what-to-expect-for-the-upcoming-deprecation-of-ftp-in-firefox/

If you do FTP a lot you could always use a FTP client such as the long running open source FileZilla ftp client (no relations to Mozilla) https://filezilla-project.org/index.php