You are using the "FileZilla" FTP software and have activated TLS for secure transmission. You have updated FileZilla to the latest version and have been unable to connect to the server since then.
Under certain circumstances the server does not support the preset TLS version of Filezilla or not yet or no longer.
How to fix your problem:
To solve your problem, start your "FileZilla" software.
- In Filezilla go to 'Edit' -> 'Settings' -> 'Connection'
- In the 'TLS Options' area, select 'TLS 1.0' as the minimum TLS version
Then try again to establish a connection to the server. If that still doesn't work, temporarily disable TLS or use WebDAV or WebFTP.