Issue Backup xmlSchemaParse() failed after upgrade to Obsidian

[PawelK]

Hello,

After upgrade Plesk to Obsidian I have error in Backup Manager :
xmlSchemaParse() failed

System : Ubuntu Xenial
Plesk Version : Obsidian 18.0.20

I see errors in the logs (/var/log/plesk/PMM/pmmcli.log) :

2019-10-26 20:27:03.232|22298] DEBUG: send-error-report /opt/psa/admin/bin/send-error-report <?xml version="1.0" ?><error><file>pmmcli, &lt;class 'libxml2.parserError'&gt;</file><line>0</line><message>xmlSchemaParse() failed</m
essage><trace> File &quot;/usr/lib/python2.7/runpy.py&quot;, line 174, in _run_module_as_main
&quot;__main__&quot;, fname, loader, pkg_name)
File &quot;/usr/lib/python2.7/runpy.py&quot;, line 72, in _run_code
exec code in run_globals
File &quot;/opt/psa/admin/sbin/pmmcli/__main__.py&quot;, line 25, in &lt;module&gt;
bootstrap_pex(__entry_point__)
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex_bootstrapper.py&quot;, line 98, in bootstrap_pex
pex.PEX(entry_point).execute()
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py&quot;, line 324, in execute
self._wrap_coverage(self._wrap_profiling, self._execute)
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py&quot;, line 254, in _wrap_coverage
runner(*args)
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py&quot;, line 286, in _wrap_profiling
runner(*args)
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py&quot;, line 367, in _execute
return self.execute_entry(self._pex_info.entry_point)
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py&quot;, line 425, in execute_entry
runner(entry_point)
File &quot;/opt/psa/admin/sbin/pmmcli/.bootstrap/_pex/pex.py&quot;, line 430, in execute_module
runpy.run_module(module_name, run_name='__main__')
File &quot;/usr/lib/python2.7/runpy.py&quot;, line 192, in run_module
fname, loader, pkg_name)
File &quot;/usr/lib/python2.7/runpy.py&quot;, line 72, in _run_code
exec code in run_globals
File &quot;/opt/psa/admin/sbin/pmmcli/pmmcli.py&quot;, line 3030, in &lt;module&gt;
File &quot;/opt/psa/admin/sbin/pmmcli/pmmcli.py&quot;, line 3023, in main
File &quot;/opt/psa/admin/sbin/pmmcli/pmmcli.py&quot;, line 2917, in logUnhandledError
File &quot;/opt/psa/admin/sbin/pmmcli/error_reporter.py&quot;, line 18, in sendException
stack_trace = traceback.format_stack()
</trace></error>
[2019-10-26 20:27:03.236|22298] INFO: Executing asynchronously <subprocess[22300] '/opt/psa/admin/bin/send-error-report send-error-report pmm'>
[2019-10-26 20:27:03.237|22298] INFO: Outgoing packet:
<?xml version="1.0" ?><response>
<errcode>1001</errcode>
<errmsg>xmlSchemaParse() failed</errmsg>
</response>​

I try reinstall python-libxml2 python python2.7 python3 python3.5 - no change.

Any help ? Tip ?