Problem installing Google Analytics and other add-ons

Hello, dear Plonists,

'Google Analytics' fails to install under 'Site setups -> Modules' and returns an error message. Here is its text traceback (I receive the same type of error message when trying to install other add-ons, such as the 'webcouturier.dropdowmenu' add-on):


Traceback (innermost last):
Module ZPublisher.Publish, line 138, in publish
Module ZPublisher.mapply, line 77, in mapply
Module ZPublisher.Publish, line 48, in call_object
Module Products.CMFPlone.controlpanel.browser.quickinstaller, line 689, in call
Module Products.CMFPlone.controlpanel.browser.quickinstaller, line 454, in install_product
Module Products.GenericSetup.tool, line 388, in runAllImportStepsFromProfile

  • traceback_info: profile-collective.googleanalytics:default
    Module Products.GenericSetup.tool, line 1433, in _runImportStepsFromContext
    Module Products.GenericSetup.tool, line 1245, in _doRunImportStep
  • traceback_info: jsregistry
    Module Products.CMFPlone.resources.exportimport.jsregistry, line 15, in importJSRegistry
    Module Products.CMFPlone.resources.exportimport.resourceregistry, line 36, in importResRegistry
    Module Products.GenericSetup.utils, line 512, in _importBody
    Module Products.CMFPlone.resources.exportimport.resourceregistry, line 163, in _importNode
    Module Products.CMFPlone.resources.browser.cook, line 163, in cookWhenChangingSettings
    Module Products.CMFPlone.resources.browser.combine, line 169, in combine_bundles
    Module Products.CMFPlone.resources.browser.combine, line 115, in write_js
    Module plone.resource.directory, line 162, in writeFile
    Module OFS.Image, line 139, in init
    Module OFS.Image, line 544, in _read_data
    Module transaction._manager, line 147, in savepoint
    Module transaction._transaction, line 228, in savepoint
    Module transaction._transaction, line 344, in _saveAndRaiseCommitishError
    Module transaction._transaction, line 225, in savepoint
    Module transaction._transaction, line 713, in init
    Module ZODB.Connection, line 1000, in savepoint
    Module ZODB.Connection, line 547, in _commit
    Module ZODB.Connection, line 579, in _store_objects
    Module ZODB.serialize, line 419, in serialize
    Module ZODB.serialize, line 428, in _dump
    PicklingError: Can't pickle <class 'plone.formwidget.recaptcha.interfaces.IReCaptchaLayer'>: import of module plone.formwidget.recaptcha.interfaces failed

I am running Plone5 on a Virtual Private Server (VPS) with Ubuntu 18.04. I also would like to install the 'Open Web Analyser' (instead of Google Analytics). Any hint or advice in either or both of these issues would be very much appreciated.

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