do-release-upgrade error: SystemError: E:Unable to correct problems, you have held broken packages

[Rafael Herrero Solís]

Today i tried to upgrade my ubuntu server:
Distributor ID: Ubuntu
Description: Ubuntu 16.04.6 LTS
Release: 16.04
Codename: xenial

But i got a nasty error:

---------------------------------------------------------------------------------------------------
Investigating (4) python3-twisted [ amd64 ] < none -> 17.9.0-2 > ( python )
Broken python3-twisted:amd64 Depends on python3-zope.interface [ amd64 ] < 4.3.2-1+ubuntu16.04.1+certbot+1 > ( zope ) (>= 4.0.2)
  Considering python3-zope.interface:amd64 10000 as a solution to python3-twisted:amd64 10000
  Considering python3-zope.interface:amd64 10000 as a solution to python3-twisted:amd64 10000
Done

Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-td6fitjd/bionic", line 8, in <module>
    sys.exit(main())
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeMain.py", line 238, in main
    if app.run():
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 2053, in run
    return self.fullUpgrade()
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 1962, in fullUpgrade
    if not self.askDistUpgrade():
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 1142, in askDistUpgrade
    changes = self.calcDistUpgrade()
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 1109, in calcDistUpgrade
    if not self.cache.installTasks(self.tasks):
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeCache.py", line 856, in installTasks
    pkg.mark_install()
  File "/usr/lib/python3/dist-packages/apt/package.py", line 1304, in mark_install
    fixer.resolve(True)
SystemError: E:Unable to correct problems, you have held broken packages.
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/problem_report.py", line 497, in add_to_existing
    self.write(f)
  File "/usr/lib/python3/dist-packages/problem_report.py", line 450, in write
    block = f.read(1048576)
  File "/usr/lib/python3.5/codecs.py", line 321, in decode
    (result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte

Original exception was:
Traceback (most recent call last):
  File "/tmp/ubuntu-release-upgrader-td6fitjd/bionic", line 8, in <module>
    sys.exit(main())
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeMain.py", line 238, in main
    if app.run():
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 2053, in run
    return self.fullUpgrade()
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 1962, in fullUpgrade
    if not self.askDistUpgrade():
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 1142, in askDistUpgrade
    changes = self.calcDistUpgrade()
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeController.py", line 1109, in calcDistUpgrade
    if not self.cache.installTasks(self.tasks):
  File "/tmp/ubuntu-release-upgrader-td6fitjd/DistUpgrade/DistUpgradeCache.py", line 856, in installTasks
    pkg.mark_install()
  File "/usr/lib/python3/dist-packages/apt/package.py", line 1304, in mark_install
    fixer.resolve(True)
SystemError: E:Unable to correct problems, you have held broken packages.
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It was not possible to scroll up to see the rest of the error.

[Juan Villa (gianpamx)]

I had the same problem.
After the
 SystemError: E:Unable to correct problems, you have held broken packages.
line
the next one was a prompt about retrying. I did retry and everything worked