We are having the exact same issues after upgrading from the 0.9.6 to 1.6.7. All of our vendors trying to send files are only able to create a blank file in the directory and all receive the error below.
"425 Unable to build data connection: TLS session of data connection not resumed."
Server is configured to accept a minimum TLS version of 1.2, is configured for passive mode with a port range of 50000-50050 with external IP configured and requires explicit FTP over TLS.
We have also confirmed this issue does not occur when using the FileZilla client and only seems to be affecting those accessing via non-FileZilla clients.
2023-04-26T21:41:58.946Z DI [REDACTED] Session 0x184e4e52990 with ID 756 created.\
2023-04-26T21:41:58.946Z << [REDACTED] 220-FileZilla Server 1.6.7\
2023-04-26T21:41:58.946Z << [REDACTED] 220 Please visit
https://filezilla-project.org/\
2023-04-26T21:41:58.992Z >> [REDACTED] AUTH TLS\
2023-04-26T21:41:58.992Z << [REDACTED] 234 Using authentication type TLS.\
2023-04-26T21:41:58.992Z DV [REDACTED] tls_layer_impl::server_handshake()\
2023-04-26T21:41:58.992Z DV [REDACTED] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:58.992Z DV [REDACTED] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.086Z DV [REDACTED] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.133Z DV [REDACTED] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.133Z DI [REDACTED] TLS Handshake successful\
2023-04-26T21:41:59.133Z DI [REDACTED] Protocol: TLS1.2, Key exchange: ECDHE-SECP256R1-RSA-PSS-RSAE-SHA256, Cipher: AES-256-GCM, MAC: AEAD, ALPN: \
2023-04-26T21:41:59.180Z >> [REDACTED] USER Test\
2023-04-26T21:41:59.180Z DI [Throttled Authenticator] Authenticating user Test from IP xxx.xxx.xxx.xxx.\
2023-04-26T21:41:59.180Z << [REDACTED] 331 Please, specify the password.\
2023-04-26T21:41:59.242Z >> [REDACTED] PASS ****\
2023-04-26T21:41:59.242Z DV [File-based Authenticator] Authenticating user 'Test'. Methods requested: (\{ id = 1, set = 1 \}). Available methods: [1].\
2023-04-26T21:41:59.336Z DV [File-based Authenticator] Auth method \{ id = 1, set = 1 \} passed for user 'Test'.\
2023-04-26T21:41:59.336Z DV [File-based Authenticator] impersonation_token: \{ username: "", home: "" \}\
2023-04-26T21:41:59.336Z DV [File-based Authenticator] Authentication for user 'Test' is complete.\
2023-04-26T21:41:59.336Z DV [File-based Authenticator] impersonation_token: \{ username: "", home: "" \}\
2023-04-26T21:41:59.336Z << [REDACTED SESSION] 230 Login successful.\
2023-04-26T21:41:59.383Z >> [REDACTED SESSION] PBSZ 0\
2023-04-26T21:41:59.383Z << [REDACTED SESSION] 200 PBSZ=0\
2023-04-26T21:41:59.430Z >> [REDACTED SESSION] PROT P\
2023-04-26T21:41:59.430Z << [REDACTED SESSION] 200 Protection level set to P\
2023-04-26T21:41:59.477Z >> [REDACTED SESSION] TYPE A\
2023-04-26T21:41:59.477Z << [REDACTED SESSION] 200 Type set to A\
2023-04-26T21:41:59.524Z >> [REDACTED SESSION] PASV\
2023-04-26T21:41:59.524Z DV [REDACTED SESSION] Trying listen(1, 50037) for data connection.\
2023-04-26T21:41:59.524Z << [REDACTED SESSION] 227 Entering Passive Mode (xxx,xxx,xxx,xxx,195,117)\
2023-04-26T21:41:59.586Z >> [REDACTED SESSION] STOR Test.CSV\
2023-04-26T21:41:59.586Z << [REDACTED SESSION] 150 About to start data transfer.\
2023-04-26T21:41:59.617Z DV [REDACTED SESSION] session::on_socket_event(): source = data listen, flag = 2, error = 0, state = -1\
2023-04-26T21:41:59.633Z DV [REDACTED SESSION] tls_layer_impl::server_handshake()\
2023-04-26T21:41:59.633Z DV [REDACTED SESSION] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.633Z DV [REDACTED SESSION] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.633Z DV [REDACTED SESSION] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.680Z DV [REDACTED SESSION] tls_layer_impl::continue_handshake()\
2023-04-26T21:41:59.680Z DI [REDACTED SESSION] TLS Handshake successful\
2023-04-26T21:41:59.680Z DI [REDACTED SESSION] Protocol: TLS1.2, Key exchange: ECDHE-SECP256R1-RSA-PSS-RSAE-SHA256, Cipher: AES-256-GCM, MAC: AEAD, ALPN: \
2023-04-26T21:41:59.680Z DV [REDACTED SESSION] session::on_socket_event(): source = data, flag = 2, error = 0, state = 2\
2023-04-26T21:41:59.680Z !! [REDACTED SESSION] TLS session of data connection not resumed.\
2023-04-26T21:41:59.680Z << [REDACTED SESSION] 425 Unable to build data connection: TLS session of data connection not resumed.\
2023-04-26T21:41:59.868Z >> [REDACTED SESSION] QUIT\
2023-04-26T21:41:59.868Z << [REDACTED SESSION] 221 Goodbye.\
2023-04-26T21:41:59.868Z DV [REDACTED SESSION] tls_layer_impl::shutdown()\
2023-04-26T21:41:59.868Z DV [REDACTED SESSION] tls_layer_impl::continue_shutdown()\
2023-04-26T21:41:59.899Z == [FTP Server] Session 756 ended gracefully.\
2023-04-26T21:41:59.899Z DI [REDACTED] Session 0x184e4e52990 with ID 756 destroyed.}