Various operations fail in Plesk: Failed to read data from stream Process output

[mahesh]

Question:
Various operations fail in Plesk: Failed to read data from stream Process output
Symptoms

• When opening Plesk Backup Manager or removing a domain in Plesk, the operation fails with:

Internal Error: Failed to parse response. Reason: Failed to read data from stream Process output

• When creating a domain in Plesk, the operation fails with:

Creating physical hosting
phpinimng failed: Traceback (most recent call last):
...
ImportError: cannot import name 'sysconfig' from 'distutils' (/usr/lib/python3.7/distutils/__init__.py):

• The pmmcli utility fails with "ImportError":

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#/usr/local/psa/admin/bin/pmmcli --help
...
ImportError: No module named libxml2

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#/usr/local/psa/admin/bin/pmmcli --help
...
ImportError: cannot import name 'etree' from 'lxml' (/usr/lib/python3/dist-packages/lxml/__init__.py)
Cause
/usr/bin/python3 is linked to a non-default Python version.

Resolution
1.Connect to the Plesk server via SSH.

2.Remove the invalid link:

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#unlink /usr/bin/python3
3.Link /usr/bin/python3to /usr/bin/python3.6:

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#ln -s /usr/bin/python3.6 /usr/bin/python3