Error
Failed to start service :
Starting ftp server: proftpdca proftpd[2162]: mod_tls/2.4.3: compiled using OpenSSL version ‘OpenSSL 1.0.1e 11 Feb 2013’ headers, but linked to OpenSSL version ‘OpenSSL 1.0.1t 3 May 2016’ library
ca proftpd[2162]: mod_sftp/0.9.8: compiled using OpenSSL version ‘OpenSSL 1.0.1e 11 Feb 2013’ headers, but linked to OpenSSL version ‘OpenSSL 1.0.1t 3 May 2016’ library
ca proftpd[2162]: mod_tls_memcache/0.1: notice: unable to register ‘memcache’ SSL session cache: Memcache support not enabled
ca proftpd[2162]: mod_dso/0.5: module ‘mod_tls.c’ already loaded
ca proftpd[2162]: Fatal: LoadModule: error loading module ‘mod_tls.c’: Operation not permitted on line 5 of ‘/etc/proftpd/conf.d/virtualmin.conf’
failed!
It looks like you’ve upgraded proftpd to a new version, but your openssl library is older than what proftpd was built for. Have you enabled additional repositories or perhaps switched off of stable (if this is debian/ubuntu)?