Hello Sergey,
here the output log created by your command:
[2016-10-19 09:56:30.320|12984] INFO: pmm-ras started : /usr/local/psa/admin/bin/pmm-ras --check-repository --dump-storage=ftp://
[email protected]/backupserver/cloudlinux --use-ftp-passive-mode --debug --verbose --session-path=/var/log/plesk/PMM
[2016-10-19 09:56:30.320|12984] INFO: Repository 'ftp://qnapafdox.dyndns-office.com/backupserver/cloudlinux': Initializing...
[2016-10-19 09:56:30.320|12984] INFO: Transport: Get repository transport ftp://qnapafdox.dyndns-office.com/backupserver/cloudlinux
[2016-10-19 09:56:30.320|12984] INFO: Transport: Init credentials for user 'ftpbackupsrv'
[2016-10-19 09:56:30.320|12984] INFO: Curl version: 0x72300
[2016-10-19 09:56:30.322|12984] INFO: Repository 'ftp://qnapafdox.dyndns-office.com/backupserver/cloudlinux': Initialized
[2016-10-19 09:56:30.322|12984] INFO: Test stage: Check directory access
[2016-10-19 09:56:30.322|12984] INFO: Transport: List dir /
[2016-10-19 09:56:30.322|12984] INFO: Ftp init url ftp://qnapafdox.dyndns-office.com/backupserver/cloudlinux/
[2016-10-19 09:56:30.323|12984] INFO: Created temp file: /usr/local/psa/PMM/tmp/repo_transport_tmp_PQe8zo
[2016-10-19 09:56:30.323|12984] INFO: Ftp extended list dir
[2016-10-19 09:56:40.325|12984] INFO: Curl output :
[2016-10-19 09:56:40.325|12984] INFO: * Hostname was NOT found in DNS cache
[2016-10-19 09:56:40.325|12984] INFO: * Trying 151.66.143.22...
[2016-10-19 09:56:40.325|12984] INFO: * Connected to qnapafdox.dyndns-office.com (151.66.143.22) port 21 (#0)
[2016-10-19 09:56:40.325|12984] INFO: < 220 NASFTPD Turbo station 1.3.5a Server (ProFTPD) [192.170.1.50]
[2016-10-19 09:56:40.325|12984] INFO: > USER ftpbackupsrv
[2016-10-19 09:56:40.325|12984] INFO: < 331 Password required for ftpbackupsrv
[2016-10-19 09:56:40.325|12984] INFO: < 230 User ftpbackupsrv logged in
[2016-10-19 09:56:40.325|12984] INFO: > PWD
[2016-10-19 09:56:40.326|12984] INFO: < 257 "/" is the current directory
[2016-10-19 09:56:40.326|12984] INFO: * Entry path is '/'
[2016-10-19 09:56:40.326|12984] INFO: > CWD backupserver
[2016-10-19 09:56:40.326|12984] INFO: * ftp_perform ends with SECONDARY: 0
[2016-10-19 09:56:40.326|12984] INFO: < 250 CWD command successful
[2016-10-19 09:56:40.326|12984] INFO: > CWD cloudlinux
[2016-10-19 09:56:40.326|12984] INFO: < 250 CWD command successful
[2016-10-19 09:56:40.326|12984] INFO: > EPSV
[2016-10-19 09:56:40.326|12984] INFO: * Connect data stream passively
[2016-10-19 09:56:40.326|12984] INFO: < 229 Entering Extended Passive Mode (|||56408|)
[2016-10-19 09:56:40.326|12984] INFO: * Hostname was NOT found in DNS cache
[2016-10-19 09:56:40.326|12984] INFO: * Trying 151.66.143.22...
[2016-10-19 09:56:40.326|12984] INFO: * Connecting to 151.66.143.22 (151.66.143.22) port 56408
[2016-10-19 09:56:40.326|12984] INFO: * Operation timed out after 10001 milliseconds with 0 bytes received
[2016-10-19 09:56:40.326|12984] INFO: * Closing connection 0
[2016-10-19 09:56:40.326|12984] INFO:
[2016-10-19 09:56:40.326|12984] INFO: Curl error (28): Timeout was reached
[2016-10-19 09:56:40.326|12984] INFO: CurlError[76931fac-9dab-42b3-86c2-48b87d6ae33f]: Curl error: Timeout was reached [./ftp.cpp:484]
void plesk::tFtpConnection::ListEx(std::vector<plesk::FtpFileInfo, std::allocator<plesk::FtpFileInfo> >&)
[2016-10-19 09:56:40.327|12984] INFO: pmm-ras finished. Exit code: 126
thanks.