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.