[NC18] Document Server and OnlyOffice not working

Hello,

somehow i cannot make OnlyOffice work. When i create a file and try to open it, i get 2 error messages in Nextcloud Log and its not loading. Community Document Server is activated and OnlyOffice is configured to know where it is.

Synology DSM 6.2
PHP 7.3
Apache 2.4

Any Suggestions?
Thank you in advance

Steps to reproduce

Create data.xls
open

Expected behaviour

open data.xls in OnlyOffice

Actual behaviour

“ONLYOFFICE ist zurzeit nicht erreichbar. Bitte wende Dich an Deinen Administrator”

file is not loading with error message ONLYOFFICE not reachable

Server configuration detail

Operating system: Linux 4.4.59+ #24922 SMP PREEMPT Mon Aug 19 12:13:37 CST 2019 x86_64 Synology DSM 6.2

Webserver: Apache/2.4.39 (Unix) (fpm-fcgi)

Database: mysql 10.3.21

PHP version:

7.3.11
Modules loaded: Core, date, libxml, pcre, zlib, ctype, dom, fileinfo, filter, hash, json, mbstring, pcntl, SPL, PDO, readline, Reflection, session, SimpleXML, standard, tokenizer, xml, xmlreader, xmlwriter, mysqlnd, cgi-fcgi, apcu, bcmath, bz2, calendar, curl, exif, ftp, gd, gettext, gmp, iconv, imap, intl, ldap, mailparse, mysqli, openssl, pdo_dblib, pdo_mysql, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, shmop, soap, sockets, sodium, sqlite3, ssh2, sysvmsg, sysvsem, sysvshm, wddx, xmlrpc, xsl, zip, Zend OPcache

Nextcloud version: 18.0.1 RC2 - 18.0.1.1

Updated from an older Nextcloud/ownCloud or fresh install:

Where did you install Nextcloud from: unknown

Signing status

Array
(
)

List of activated apps
Enabled:
 - accessibility: 1.4.0
 - activity: 2.11.0
 - bruteforcesettings: 1.5.0
 - cloud_federation_api: 1.1.0
 - comments: 1.8.0
 - dav: 1.14.0
 - documentserver_community: 0.1.5
 - federatedfilesharing: 1.8.0
 - federation: 1.8.0
 - files: 1.13.1
 - files_pdfviewer: 1.7.0
 - files_rightclick: 0.15.2
 - files_sharing: 1.10.1
 - files_trashbin: 1.8.0
 - files_versions: 1.11.0
 - files_videoplayer: 1.7.0
 - firstrunwizard: 2.7.0
 - issuetemplate: 0.6.0
 - logreader: 2.3.0
 - lookup_server_connector: 1.6.0
 - nextcloud_announcements: 1.7.0
 - notifications: 2.6.0
 - oauth2: 1.6.0
 - onlyoffice: 4.1.4
 - password_policy: 1.8.0
 - photos: 1.0.0
 - privacy: 1.2.0
 - provisioning_api: 1.8.0
 - recommendations: 0.6.0
 - serverinfo: 1.8.0
 - settings: 1.0.0
 - sharebymail: 1.8.0
 - support: 1.1.0
 - survey_client: 1.6.0
 - systemtags: 1.8.0
 - text: 2.0.0
 - theming: 1.9.0
 - twofactor_backupcodes: 1.7.0
 - updatenotification: 1.8.0
 - viewer: 1.2.0
 - workflowengine: 2.0.0
Disabled:
 - admin_audit
 - encryption
 - files_external
 - user_ldap

Configuration (config/config.php)
{
    "instanceid": "***REMOVED SENSITIVE VALUE***",
    "passwordsalt": "***REMOVED SENSITIVE VALUE***",
    "secret": "***REMOVED SENSITIVE VALUE***",
    "trusted_domains": [
        "lalas-backup.synology.me"
    ],
    "datadirectory": "***REMOVED SENSITIVE VALUE***",
    "dbtype": "mysql",
    "version": "18.0.1.1",
    "overwrite.cli.url": "https:\/\/xxx.xxx.xxx\/cloud",
    "dbname": "***REMOVED SENSITIVE VALUE***",
    "dbhost": "***REMOVED SENSITIVE VALUE***",
    "dbport": "",
    "dbtableprefix": "oc_",
    "mysql.utf8mb4": true,
    "dbuser": "***REMOVED SENSITIVE VALUE***",
    "dbpassword": "***REMOVED SENSITIVE VALUE***",
    "installed": true,
    "memcache.local": "\\OC\\Memcache\\APCu",
    "maintenance": false,
    "updater.release.channel": "beta",
    "updater.secret": "***REMOVED SENSITIVE VALUE***",
    "theme": "",
    "loglevel": 2
}

Are you using external storage, if yes which one:

Are you using encryption:

Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/…

Client configuration

Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:73.0) Gecko/20100101 Firefox/73.0

Operating system:

Logs

Web server error log
Insert your web server log here 
Nextcloud log
[index] Error: Exception: trim() expects parameter 1 to be string, bool given at <<closure>>

0. /volume1/web/cloud/lib/private/AppFramework/App.php line 125
   OC\AppFramework\Http\Dispatcher->dispatch(OCA\DocumentServ ... {}, "webApps")
1. /volume1/web/cloud/lib/private/AppFramework/Routing/RouteActionHandler.php line 47
   OC\AppFramework\App::main("OCA\\DocumentSe ... r", "webApps", OC\AppFramework\ ... {}, {path: "apps/api ... "})
2. <<closure>>
   OC\AppFramework\Routing\RouteActionHandler->__invoke({path: "apps/api ... "})
3. /volume1/web/cloud/lib/private/Route/Router.php line 299
   call_user_func(OC\AppFramework\ ... {}, {path: "apps/api ... "})
4. /volume1/web/cloud/lib/base.php line 1008
   OC\Route\Router->match("/apps/documents ... s")
5. /volume1/web/cloud/index.php line 38
   OC::handleRequest()

GET /index.php/apps/documentserver_community/web-apps/apps/api/documents/api.js
from 37.201.22.10 by Basti at 2020-02-12T23:08:42+00:00

[documentserver_community] Error: OCA\DocumentServer\Document\DocumentConversionException: ./x2t: /lib/libstdc++.so.6: no version information available (required by ./libgraphics.so)
./x2t: /lib/libstdc++.so.6: no version information available (required by ./libicuuc.so.58)
./x2t: /lib/libstdc++.so.6: no version information available (required by ./libicuuc.so.58)
Empty sFileFrom or sFileTo
 at <<closure>>

 0. /volume1/web/cloud/apps/documentserver_community/lib/Document/ConverterBinary.php line 72
    OCA\DocumentServer\Document\ConverterBinary->run("")
 1. /volume1/web/cloud/apps/documentserver_community/lib/SetupCheck.php line 34
    OCA\DocumentServer\Document\ConverterBinary->test()
 2. /volume1/web/cloud/apps/documentserver_community/lib/Controller/StaticController.php line 89
    OCA\DocumentServer\SetupCheck->check()
 3. /volume1/web/cloud/lib/private/AppFramework/Http/Dispatcher.php line 170
    OCA\DocumentServer\Controller\StaticController->webApps("apps/api/documents/api.js")
 4. /volume1/web/cloud/lib/private/AppFramework/Http/Dispatcher.php line 99
    OC\AppFramework\Http\Dispatcher->executeController(OCA\DocumentServ ... {}, "webApps")
 5. /volume1/web/cloud/lib/private/AppFramework/App.php line 125
    OC\AppFramework\Http\Dispatcher->dispatch(OCA\DocumentServ ... {}, "webApps")
 6. /volume1/web/cloud/lib/private/AppFramework/Routing/RouteActionHandler.php line 47
    OC\AppFramework\App::main("OCA\\DocumentSe ... r", "webApps", OC\AppFramework\ ... {}, {path: "apps/api ... "})
 7. <<closure>>
    OC\AppFramework\Routing\RouteActionHandler->__invoke({path: "apps/api ... "})
 8. /volume1/web/cloud/lib/private/Route/Router.php line 299
    call_user_func(OC\AppFramework\ ... {}, {path: "apps/api ... "})
 9. /volume1/web/cloud/lib/base.php line 1008
    OC\Route\Router->match("/apps/documents ... s")
10. /volume1/web/cloud/index.php line 38
    OC::handleRequest()

GET /index.php/apps/documentserver_community/web-apps/apps/api/documents/api.js
from 37.201.22.10 by Basti at 2020-02-12T23:08:42+00:00
Browser log

what about your OO installation and license.
I have the OO integration (not the community or entreprise wich not works with nextcloud) on over server

I am using the build in solution from Nextcloud 18. Installed OnlyOffice and Document Server app.