I got the following log, please have a look.
2019-06-17 11:44:49.271 Opening log file.
2019-06-17 11:44:49.271 INFO FileLogWriter(4)[74] Info: Assembly: Rebex.Common 2019 R2 for .NET 4.0-4.7
2019-06-17 11:44:49.271 INFO FileLogWriter(4)[74] Info: Platform: Windows 6.2.9200 32-bit; CLR: 4.0.30319.42000
2019-06-17 11:44:49.294 DEBUG FileLogWriter(4)[74] Info: Culture: en; Windows-1252
2019-06-17 11:44:49.313 DEBUG Sftp(7)[74] SSH: Allowed authentication methods for 'u_db-transfer-mngmt': publickey, keyboard-interactive.
2019-06-17 11:44:49.313 DEBUG Sftp(7)[74] SSH: Trying public key authentication for 'u_db-transfer-mngmt'.
2019-06-17 11:44:51.222 DEBUG Sftp(7)[74] SSH: Authentication successful.
2019-06-17 11:44:51.222 DEBUG Sftp(7)[74] SSH: Opening channel 'session' (initial window size: 131072, max packet size: 129024).
2019-06-17 11:44:51.234 DEBUG Sftp(7)[84] SSH: Received debug message: /var/sftp/u_db-transfer-mngmt/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
2019-06-17 11:44:51.274 DEBUG Sftp(7)[74] SSH: Requesting subsystem 'sftp'.
2019-06-17 11:44:51.277 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 0 -> 2097152.
2019-06-17 11:44:51.277 INFO Sftp(7)[74] Command: SSH_FXP_INIT (4)
2019-06-17 11:44:51.283 INFO Sftp(7)[74] Response: SSH_FXP_VERSION (3, 5 extensions)
2019-06-17 11:44:51.283 INFO Sftp(7)[74] Info: Using SFTP v3 on a Unix-like platform.
2019-06-17 11:44:51.283 INFO Sftp(7)[74] Command: SSH_FXP_REALPATH (1, '.')
2019-06-17 11:44:51.285 INFO Sftp(7)[74] Response: SSH_FXP_NAME (1, 1 item)
2019-06-17 11:44:51.285 INFO Sftp(7)[74] Info: Home directory is '/'.
2019-06-17 11:44:51.286 INFO Sftp(7)[74] Command: SSH_FXP_OPEN (2, '/db/db.sqlite', 26)
2019-06-17 11:44:51.287 INFO Sftp(7)[74] Response: SSH_FXP_HANDLE (2, 0x0)
2019-06-17 11:44:51.289 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (3, 0x0, 0, 28672 bytes)
2019-06-17 11:44:51.289 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (4, 0x0, 28672, 28672 bytes)
2019-06-17 11:44:51.289 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (5, 0x0, 57344, 28672 bytes)
2019-06-17 11:44:51.292 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (6, 0x0, 86016, 28672 bytes)
2019-06-17 11:44:51.292 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (7, 0x0, 114688, 28672 bytes)
2019-06-17 11:44:51.292 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (8, 0x0, 143360, 28672 bytes)
2019-06-17 11:44:51.294 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (9, 0x0, 172032, 28672 bytes)
2019-06-17 11:44:51.320 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (10, 0x0, 200704, 28672 bytes)
2019-06-17 11:44:51.320 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (11, 0x0, 229376, 28672 bytes)
2019-06-17 11:44:51.347 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (3, 0, 'Success')
2019-06-17 11:44:51.347 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (12, 0x0, 258048, 28672 bytes)
2019-06-17 11:44:51.374 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (4, 0, 'Success')
2019-06-17 11:44:51.374 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (13, 0x0, 286720, 28672 bytes)
2019-06-17 11:44:51.398 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1781370 -> 1896245.
2019-06-17 11:44:51.398 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (5, 0, 'Success')
2019-06-17 11:44:51.401 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (14, 0x0, 315392, 28672 bytes)
2019-06-17 11:44:51.421 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (6, 0, 'Success')
2019-06-17 11:44:51.422 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (15, 0x0, 344064, 28672 bytes)
2019-06-17 11:44:51.445 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (7, 0, 'Success')
2019-06-17 11:44:51.446 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (16, 0x0, 372736, 28672 bytes)
2019-06-17 11:44:51.469 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (8, 0, 'Success')
2019-06-17 11:44:51.469 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (17, 0x0, 401408, 28672 bytes)
2019-06-17 11:44:51.493 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1781441 -> 1896245.
2019-06-17 11:44:51.494 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (9, 0, 'Success')
2019-06-17 11:44:51.874 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (34, 0x0, 888832, 28672 bytes)
2019-06-17 11:44:51.898 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (26, 0, 'Success')
2019-06-17 11:44:51.898 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (35, 0x0, 917504, 28672 bytes)
2019-06-17 11:44:51.923 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (27, 0, 'Success')
2019-06-17 11:44:51.924 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (36, 0x0, 946176, 28672 bytes)
2019-06-17 11:44:51.947 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (28, 0, 'Success')
2019-06-17 11:44:51.947 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (37, 0x0, 974848, 28672 bytes)
2019-06-17 11:44:51.970 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1781441 -> 1896245.
2019-06-17 11:44:51.970 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (29, 0, 'Success')
2019-06-17 11:44:51.970 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (38, 0x0, 1003520, 28672 bytes)
2019-06-17 11:44:51.994 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (30, 0, 'Success')
2019-06-17 11:44:51.995 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (39, 0x0, 1032192, 28672 bytes)
2019-06-17 11:44:52.019 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (31, 0, 'Success')
2019-06-17 11:44:52.019 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (40, 0x0, 1060864, 28672 bytes)
2019-06-17 11:44:52.043 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (32, 0, 'Success')
2019-06-17 11:44:52.043 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (41, 0x0, 1089536, 28672 bytes)
2019-06-17 11:44:52.066 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1781441 -> 1896245.
2019-06-17 11:44:52.067 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (33, 0, 'Success')
2019-06-17 11:44:52.067 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (42, 0x0, 1118208, 28672 bytes)
2019-06-17 11:44:52.091 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (34, 0, 'Success')
2019-06-17 11:44:52.091 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (43, 0x0, 1146880, 28672 bytes)
2019-06-17 11:44:52.114 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (35, 0, 'Success')
2019-06-17 11:44:52.115 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (44, 0x0, 1175552, 28672 bytes)
2019-06-17 11:44:52.146 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (36, 0, 'Success')
2019-06-17 11:44:52.147 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (45, 0x0, 1204224, 28672 bytes)
2019-06-17 11:44:52.162 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1781441 -> 1896245.
2019-06-17 11:44:52.162 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (37, 0, 'Success')
2019-06-17 11:44:52.163 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (46, 0x0, 1232896, 28672 bytes)
2019-06-17 11:44:52.192 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (38, 0, 'Success')
2019-06-17 11:44:52.193 DEBUG Sftp(7)[74] Command: SSH_FXP_WRITE (47, 0x0, 1261568, 20480 bytes)
2019-06-17 11:44:52.209 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (39, 0, 'Success')
2019-06-17 11:44:52.232 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (40, 0, 'Success')
2019-06-17 11:44:52.254 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1847035 -> 1961839.
2019-06-17 11:44:52.255 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (41, 0, 'Success')
2019-06-17 11:44:52.277 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (42, 0, 'Success')
2019-06-17 11:44:52.299 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (43, 0, 'Success')
2019-06-17 11:44:52.321 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (44, 0, 'Success')
2019-06-17 11:44:52.344 DEBUG Sftp(7)[84] SSH: Adjusted remote window size: 1961839 -> 2076643.
2019-06-17 11:44:52.344 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (45, 0, 'Success')
2019-06-17 11:44:52.361 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (46, 0, 'Success')
2019-06-17 11:44:52.361 DEBUG Sftp(7)[74] Response: SSH_FXP_STATUS (47, 0, 'Success')
2019-06-17 11:44:52.361 INFO Sftp(7)[74] Command: SSH_FXP_CLOSE (48, 0x0)
2019-06-17 11:44:52.363 INFO Sftp(7)[74] Response: SSH_FXP_STATUS (48, 0, 'Success')