Abonement between two NC-Server won't work

I have two NC Server with the same IP. cloud.domain1.tld and cloud.domain2.tld
They own different companies but they work together.
Now one Member of domain1 will share his calendar to am member of the domain2
But if we take the link for the Abonement we recieve:
“The remote server does not allow access to the calendar (HTTP {401} error)”

Server configuration detail

Operating system: Linux 4.4.0-165-generic #193-Ubuntu SMP Tue Sep 17 17:42:52 UTC 2019 x86_64

Webserver: Apache (fpm-fcgi)

Database: mysql 5.7.27

PHP version:

7.2.23
Modules loaded: Core, date, libxml, openssl, pcre, zlib, bz2, calendar, ctype, hash, filter, ftp, gettext, gmp, SPL, iconv, Reflection, session, standard, SimpleXML, sockets, mbstring, tokenizer, xml, cgi-fcgi, mysqlnd, bcmath, curl, dba, dom, enchant, fileinfo, gd, imagick, imap, intl, json, ldap, exif, mysqli, odbc, PDO, pdo_mysql, PDO_ODBC, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, pspell, redis, soap, sodium, sqlite3, sysvmsg, sysvsem, sysvshm, tidy, xmlreader, xmlrpc, xmlwriter, xsl, zip, ionCube Loader, Zend OPcache

Nextcloud version: 16.0.5 - 16.0.5.1

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: 1.2.0
 - activity: 2.9.1
 - announcementcenter: 3.5.1
 - apporder: 0.8.0
 - bruteforcesettings: 1.4.0
 - calendar: 1.7.1
 - camerarawpreviews: 0.7.1
 - cloud_federation_api: 0.2.0
 - comments: 1.6.0
 - dashboard: 6.0.0
 - dav: 1.9.2
 - federatedfilesharing: 1.6.0
 - federation: 1.6.0
 - files: 1.11.0
 - files_accesscontrol: 1.6.0
 - files_downloadactivity: 1.5.0
 - files_pdfviewer: 1.5.0
 - files_rightclick: 0.15.1
 - files_sharing: 1.8.0
 - files_texteditor: 2.8.0
 - files_trackdownloads: 1.5.0
 - files_trashbin: 1.6.0
 - files_versions: 1.9.0
 - files_videoplayer: 1.5.0
 - firstrunwizard: 2.5.0
 - gallery: 18.3.0
 - groupfolders: 4.1.3
 - issuetemplate: 0.5.0
 - logreader: 2.1.0
 - lookup_server_connector: 1.4.0
 - nextcloud_announcements: 1.5.0
 - notifications: 2.4.1
 - oauth2: 1.4.2
 - password_policy: 1.6.0
 - privacy: 1.0.0
 - provisioning_api: 1.6.0
 - recommendations: 0.4.0
 - serverinfo: 1.6.0
 - sharebymail: 1.6.0
 - support: 1.0.0
 - survey_client: 1.4.0
 - systemtags: 1.6.0
 - theming: 1.7.0
 - twofactor_backupcodes: 1.5.0
 - updatenotification: 1.6.0
 - viewer: 1.1.0
 - workflowengine: 1.6.0
Disabled:
 - admin_audit
 - encryption
 - files_external
 - richdocuments
 - user_ldap

Configuration (config/config.php)
{
    "instanceid": "***REMOVED SENSITIVE VALUE***",
    "passwordsalt": "***REMOVED SENSITIVE VALUE***",
    "secret": "***REMOVED SENSITIVE VALUE***",
    "trusted_domains": [
        "cloud.menke.de"
    ],
    "datadirectory": "***REMOVED SENSITIVE VALUE***",
    "dbtype": "mysql",
    "version": "16.0.5.1",
    "overwrite.cli.url": "https:\/\/cloud.menke.de",
    "dbname": "***REMOVED SENSITIVE VALUE***",
    "dbhost": "***REMOVED SENSITIVE VALUE***",
    "dbport": "",
    "dbtableprefix": "oc_",
    "mysql.utf8mb4": true,
    "dbuser": "***REMOVED SENSITIVE VALUE***",
    "dbpassword": "***REMOVED SENSITIVE VALUE***",
    "installed": true,
    "theme": "",
    "loglevel": 2,
    "maintenance": false,
    "app_install_overwrite": [
        "documents"
    ],
    "updater.secret": "***REMOVED SENSITIVE VALUE***"
}

Are you using external storage, if yes which one: local/smb/sftp/…

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 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36

Operating system: Windows 7

Browser log

loader.js:52 Refused to load the script ‘https://cloud.cornexion.com/apps/firstrunwizard/js/firstrunwizard.js’ because it violates the following Content Security Policy directive: “script-src ‘nonce-N3V6eS9ZUlA1ZEpxaUF0V1Y2RzMwdjJURDZHczMwVE1oK09yN01XcUdKTT06aFpTWW51WW8wWVE4enpJQWVKYmxtc2oyV2ZiMnJ3eS84cXZPbnJDRmZPaz0=’”. Note that ‘script-src-elem’ was not explicitly set, so ‘script-src’ is used as a fallback.

(anonymous) @ loader.js:52
cloud.cornexion.com/:1 Uncaught (in promise) Failed to load script from /apps/firstrunwizard/js/firstrunwizard.js
2about.js?v=759ef963-16:8 Uncaught (in promise) TypeError: Cannot read property ‘open’ of undefined
at about.js?v=759ef963-16:8
2/index.php/apps/calendar/v1/proxy?url=https%3A%2F%2Fcloud.menke.de%2Findex.php%2Fapps%2Fcalendar%2Fembed%2FcGLZTFdrBqJ9dYdp:1 Failed to load resource: the server responded with a status of 422 ()
vendor.js:6694 GET https://cloud.cornexion.com/index.php/apps/calendar/v1/proxy?url=https%3A%2F%2Fcloud.menke.de%2Findex.php%2Fapps%2Fcalendar%2Fembed%2FcGLZTFdrBqJ9dYdp 422