Onlyoffice issue on fresh intall

Nextcloud version (eg, 12.0.2): 18.0.2
Operating system and version (eg, Ubuntu 17.04): Debian 4.9.168
Apache or nginx version (eg, Apache 2.4.25): no idea
PHP version (eg, 7.1): PHP 7.3

The issue you are facing:
ONLYOFFICE cannot be reached. Please contact admin
Disabled Community Document Server, not starting anymore, removed ! Install not possible again: An error occured during the request. Unable to proceed.

Is this the first time you’ve seen this error? (Y/N): N (Same issue on another install)

Steps to replicate it:

  1. Nextcloud fresh install on an Infomaniak test site.
  2. Webinstaller used: setup-nextcloud.php
  3. No issue during install, all packages are working except ONLYOFFICE

The output of your Nextcloud log in Admin > Logging:

Exception: fclose() expects parameter 1 to be resource, null given
/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/AppFramework/App.php - line 125:

OC\AppFramework\Http\Dispatcher->dispatch(OCA\Settings ... {}, "enableApps")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/AppFramework/Routing/RouteActionHandler.php - line 47:

OC\AppFramework\App::main("OCA\\Settin ... r", "enableApps", OC\AppFramew ... {}, { _route: "s ... "})

<<closure>>

OC\AppFramework\Routing\RouteActionHandler->__invoke({ _route: "s ... "})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/Route/Router.php - line 299:

call_user_func(OC\AppFramew ... {}, { _route: "s ... "})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/base.php - line 1008:

OC\Route\Router->match("/settings/apps/enable")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/index.php - line 38:

OC::handleRequest()

Caused by TypeError: fclose() expects parameter 1 to be resource, null given
/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/apps/documentserver_community/lib/Document/FontManager.php - line 66:

fclose(null)

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/apps/documentserver_community/lib/LocalAppData.php - line 78:

OCA\DocumentServer\Document\FontManager->OCA\DocumentServer\Document\{closure}("*** sensiti ... *")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/apps/documentserver_community/lib/Document/FontManager.php - line 72:

OCA\DocumentServer\LocalAppData->getReadLocalPath(OC\Files\Sim ... {}, Closure {})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/apps/documentserver_community/lib/Migration/RebuildFonts.php - line 46:

OCA\DocumentServer\Document\FontManager->rebuildFonts()

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/Repair.php - line 104:

OCA\DocumentServer\Migration\RebuildFonts->run(OC\Repair {})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/legacy/app.php - line 981:

OC\Repair->run()

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/Installer.php - line 160:

OC_App::executeRepairSteps("documentserver_community", { step: "OCA ... "})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/apps/settings/lib/Controller/AppSettingsController.php - line 443:

OC\Installer->installApp("documentserver_community")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/AppFramework/Http/Dispatcher.php - line 170:

OCA\Settings\Controller\AppSettingsController->enableApps([ "documentserver_community"], [])

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/AppFramework/Http/Dispatcher.php - line 99:

OC\AppFramework\Http\Dispatcher->executeController(OCA\Settings ... {}, "enableApps")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/AppFramework/App.php - line 125:

OC\AppFramework\Http\Dispatcher->dispatch(OCA\Settings ... {}, "enableApps")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/AppFramework/Routing/RouteActionHandler.php - line 47:

OC\AppFramework\App::main("OCA\\Settin ... r", "enableApps", OC\AppFramew ... {}, { _route: "s ... "})

<<closure>>

OC\AppFramework\Routing\RouteActionHandler->__invoke({ _route: "s ... "})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/private/Route/Router.php - line 299:

call_user_func(OC\AppFramew ... {}, { _route: "s ... "})

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/lib/base.php - line 1008:

OC\Route\Router->match("/settings/apps/enable")

/home/clients/c6d25c0e6f1e6bd46e1b5ae2dc29fdcc/next/index.php - line 38:

OC::handleRequest()