The server version you are using (1.24.0) is over 6 years old, and became deprecated a very long time ago. The Web Vault version shown in your screenshot (2.25.1) never existed in Bitwarden, so your server may not be running authentic Bitwarden code.
Regardless, you need to upgrade your server a.s.a.p. — until you do so, it is unlikely that modern versions of the Bitwarden browser extension will be able to connect to your server, KDF settings notwithstanding.
I suppose an alternative, if your browser permits side loading of extensions, would be to install an ancient version of the browser extension, which should be compatible with your ancient server! 