Not returning to issuer after login

Steps to reproduce

1. Go to the SP to login
2. Enter username and password on the IdP login page.

Expected behaviour

After the account is verified, the user should be returned to the SP.

Actual behaviour

After the account is verified, the user stays at the IdP.

Server configuration

Operating system: Centos 7

Web server: Apache/2.4.29

Database: 5.5.5-10.0.34-MariaDB

PHP version: 7.1.14

Nextcloud version: (see Nextcloud admin page) 13.0.0

Where did you install Nextcloud from:

List of activated apps:

If you have access to your command line run e.g.:
sudo -u www-data php occ app:list
from within your Nextcloud installation folder

Nextcloud configuration:
{
"system": {
"instanceid": "REMOVED SENSITIVE VALUE",
"passwordsalt": "REMOVED SENSITIVE VALUE",
"secret": "REMOVED SENSITIVE VALUE",
"trusted_domains": [
"localhost",
"bestanden.covs-de-scheidsrechter.nl"
],
"datadirectory": "REMOVED SENSITIVE VALUE",
"overwrite.cli.url": "https://bestanden.covs-de-scheidsrechter.nl",
"dbtype": "mysql",
"version": "13.0.0.14",
"dbname": "REMOVED SENSITIVE VALUE",
"dbhost": "REMOVED SENSITIVE VALUE",
"dbtableprefix": "ownc_",
"dbuser": "REMOVED SENSITIVE VALUE",
"dbpassword": "REMOVED SENSITIVE VALUE",
"logtimezone": "Europe/Amsterdam",
"installed": true,
"maintenance": false,
"theme": "",
"loglevel": 2,
"htaccess.RewriteBase": "/",
"redis": {
"host": "REMOVED SENSITIVE VALUE",
"port": 6379
},
"memcache.locking": "\OC\Memcache\Redis",
"mail_from_address": "REMOVED SENSITIVE VALUE",
"mail_smtpmode": "php",
"mail_domain": "REMOVED SENSITIVE VALUE",
"updater.release.channel": "stable",
"enable_previews": true,
"enabledPreviewProviders": [
"OC\Preview\PNG",
"OC\Preview\JPEG",
"OC\Preview\GIF",
"OC\Preview\BMP",
"OC\Preview\XBitmap",
"OC\Preview\Markdown",
"OC\Preview\MP3",
"OC\Preview\TXT",
"OC\Preview\Illustrator",
"OC\Preview\Movie",
"OC\Preview\MSOffice2003",
"OC\Preview\MSOffice2007",
"OC\Preview\MSOfficeDoc",
"OC\Preview\OpenDocument",
"OC\Preview\PDF",
"OC\Preview\Photoshop",
"OC\Preview\Postscript",
"OC\Preview\StarOffice",
"OC\Preview\SVG",
"OC\Preview\TIFF",
"OC\Preview\Font"
],
"updater.secret": "REMOVED SENSITIVE VALUE"
}
}

If you have access to your command line run e.g.:
sudo -u www-data php occ config:list system
from within your Nextcloud installation folder

or

Insert your config.php content here
Make sure to remove all sensitive content such as passwords. (e.g. database password, passwordsalt, secret, smtp password, …)

Client configuration

Browser:

Operating system:

Logs

Nextcloud log (data/owncloud.log)

Insert your Nextcloud log here

Feb 25 14:53:00 simplesamlphp DEBUG [3a974c854f] Session: 'admin' not valid because we are not authenticated.
Feb 25 14:53:00 simplesamlphp DEBUG [3a974c854f] Session: 'login-admin' not valid because we are not authenticated.
Feb 25 14:53:01 simplesamlphp DEBUG [3a974c854f] Localization: using old system
Feb 25 14:53:01 simplesamlphp DEBUG [3a974c854f] Template: Reading [/var/simplesamlphp/modules/core/dictionaries/frontpage]
Feb 25 14:53:01 simplesamlphp DEBUG [3a974c854f] Template: Reading [/var/simplesamlphp/modules/core/dictionaries/frontpage]
Feb 25 14:53:01 simplesamlphp WARNING [3a974c854f] Deprecated use of new SimpleSAML\Locale\Translate::t(...) at /var/simplesamlphp/lib/SimpleSAML/XHTML/Template.php:716. The $tag-parameter can only be a string in 2.0.
Feb 25 14:53:02 simplesamlphp DEBUG [3a974c854f] Session: 'admin' not valid because we are not authenticated.
Feb 25 14:53:02 simplesamlphp DEBUG [3a974c854f] Session: 'login-admin' not valid because we are not authenticated.
Feb 25 14:53:02 simplesamlphp DEBUG [3a974c854f] Localization: using old system
Feb 25 14:53:02 simplesamlphp DEBUG [3a974c854f] Template: Reading [/var/simplesamlphp/modules/core/dictionaries/frontpage]
Feb 25 14:53:02 simplesamlphp DEBUG [3a974c854f] Template: Reading [/var/simplesamlphp/modules/core/dictionaries/frontpage]
Feb 25 14:53:04 simplesamlphp DEBUG [3a974c854f] Session: 'admin' not valid because we are not authenticated.
Feb 25 14:53:04 simplesamlphp DEBUG [3a974c854f] Session: 'login-admin' not valid because we are not authenticated.

Browser log

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log
c) ...

Start by reproducing the login flow described in the issue using the listed Nextcloud, PHP, Apache, CentOS, and MariaDB versions, then inspect the supplied SimpleSAMLphp log output and server configuration. Done means that after credentials are verified by the IdP, the user returns to the Nextcloud service provider instead of remaining at the IdP.