SFTP with Private Key not possible

[EternalStudent]

Hello Forum,
I am using BestSync 2017 Ultimate Edition since now with no issue. It is running on a Windows Server 2012 R2 Environment.
I have installed OpenSSH and the Services are Running properly. When I want to make a new Task for sftp and choosing the private key and save it, I get following error from ChilkatLog:

ChilkatLog:
FromOpenSshPrivateKey:
DllDate: Mar 14 2016
ChilkatVersion: 9.5.0.56
UnlockPrefix: wffjgxSSH
Username: FTP-SYNCH:Administrator
Architecture: Little Endian; 64-bit
VerboseLogging: 0
fromOpenSshPrivateKey:
loadPem2:
loadPem:
itemType: OPENSSH PRIVATE KEY
addPemItem:
loadAnyDerPw:
DecodeToAsn:
premature end of BER encoding (F2)
length: 115
numBytesLeft: 108
--DecodeToAsn
loadAnyAsn:
Invalid ASN.1 for public/private key
--loadAnyAsn
der_to_xml:
ASN data length exceeds remaining number of bytes available.
tag: 19
idClass: 1
bConstructed: 1
headerLen: 2
dataLen: 115
inlen: 108
Abort ASN.1 processing...
recursiveDepth: 2
Abort ASN.1 processing...
recursiveDepth: 1
--der_to_xml
der_xml: <?xml version="1.0" encoding="utf-8" ?>
<application tag="15" constructed="1">
<application tag="5" constructed="1" />
</application>
--loadAnyDerPw
--addPemItem
--loadPem
--loadPem2
Check the password, it may be incorrect.
--fromOpenSshPrivateKey
Failed.
--FromOpenSshPrivateKey
--ChilkatLog
>GetFileList: /
ChilkatLog:
OpenDir:
DllDate: Mar 14 2016
ChilkatVersion: 9.5.0.56
UnlockPrefix: wffjgxSSH
Username: FTP-SYNCH:Administrator
Architecture: Little Endian; 64-bit
VerboseLogging: 0
SshVersion: SSH-2.0-DPD SFTP-c-Server
SftpVersion: 0
Must first have an open SFTP channel (by calling InitializeSftp).
--OpenDir
--ChilkatLog
>GetFileList: /
ChilkatLog:
OpenDir:
DllDate: Mar 14 2016
ChilkatVersion: 9.5.0.56
UnlockPrefix: wffjgxSSH
Username: FTP-SYNCH:Administrator
Architecture: Little Endian; 64-bit
VerboseLogging: 0
SshVersion: SSH-2.0-DPD SFTP-c-Server
SftpVersion: 0
Must first have an open SFTP channel (by calling InitializeSftp).
--OpenDir
--ChilkatLog
>GetFileList: /
ChilkatLog:
OpenDir:
DllDate: Mar 14 2016
ChilkatVersion: 9.5.0.56
UnlockPrefix: wffjgxSSH
Username: FTP-SYNCH:Administrator
Architecture: Little Endian; 64-bit
VerboseLogging: 0
SshVersion: SSH-2.0-DPD SFTP-c-Server
SftpVersion: 0
Must first have an open SFTP channel (by calling InitializeSftp).
--OpenDir
--ChilkatLog
>GetFileList: /
ChilkatLog:
OpenDir:
DllDate: Mar 14 2016
ChilkatVersion: 9.5.0.56
UnlockPrefix: wffjgxSSH
Username: FTP-SYNCH:Administrator
Architecture: Little Endian; 64-bit
VerboseLogging: 0
SshVersion: SSH-2.0-DPD SFTP-c-Server
SftpVersion: 0
Must first have an open SFTP channel (by calling InitializeSftp).
--OpenDir
--ChilkatLog
>GetFileList: /
ChilkatLog:
OpenDir:
DllDate: Mar 14 2016
ChilkatVersion: 9.5.0.56
UnlockPrefix: wffjgxSSH
Username: FTP-SYNCH:Administrator
Architecture: Little Endian; 64-bit
VerboseLogging: 0
SshVersion: SSH-2.0-DPD SFTP-c-Server
SftpVersion: 0
Must first have an open SFTP channel (by calling InitializeSftp).
--OpenDir
--ChilkatLog

Can someone help me out here?
I would like to notice that it is working properly on this Server with the Filezilla Software.

[RiseFly]

We have used a new SFTP library to build BestSync, please download and install BestSync 2021 (Ver16.0.1.5) to see if the problem can be resolved.

[EternalStudent]

It is connecting to the host. So it looks like it is working.
I wrote to risefly@risefly.com for a one week Test Licence before I buy the upgrade.
May I have it today?

[RiseFly]

After you installing a new version, you will have 7 days for evaluating all the features of BestSync.