Feeds are shown in Feed Preview but not in Feed Items

I have a fresh WordPress installation. Just the WP RSS Aggregator plugin is installed. When i add a item source, the feed items will be shown in the Feed Preview. After i created an example post the feed items will not shown. Only the message: No feed items found.

I know the rss feed page is right because i tested already on another website. I also tried to take a look in the logs but no errors. Just the message that the feed import is started and completed. I checked every thread in google but no chance for success.
I also tested with different php versions. 7.3.0 and 7.4.0.

It must be a problem with the screen of the feed items because in the feed preview they are correctly.

Here is my configuration:

### Begin System Info ###

## Please include this information when posting support requests ##

Multi-site: No

SITE_URL: https://deutsche-blogroll.de
HOME_URL: https://deutsche-blogroll.de

Plugin Version: 4.17.3
WordPress Version: 5.3.2

Platform: Windows
Browser Name: Chrome
Browser Version: 79.0.3945.130
User Agent String: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

PHP Version: 7.4.0
MySQL Version: 5.6.42-log (mysqli)
Web Server Info: Apache/2.4.41 (Unix)

PHP Safe Mode: No
PHP Memory Limit: 256M
PHP Post Max Size: 76M
PHP Time Limit: 120

WP_DEBUG: Disabled

WP Table Prefix: Length: 3 Status: Acceptable

Show On Front: posts
Page On Front: #0
Page For Posts: #0

Session: Disabled
Session Name: PHPSESSID
Cookie Path: /
Save Path: 2;/var/tmp
Use Cookies: On
Use Only Cookies: On

UPLOAD_MAX_FILESIZE: 64MB
POST_MAX_SIZE: 76MB
WordPress Memory Limit: 40MB
DISPLAY ERRORS: N/A
FSOCKOPEN: Your server supports fsockopen.

PLUGIN MODULES:

– core
– addons
– wordpress
– assets
– importer
– feed_sources
– feed_items
– feed_blacklist
– feed_display
– feed_shortcode
– feed_templates
– gutenberg_block
– images
– custom_feed
– rest_api
– tools
– tools/bulk_add
– tools/blacklist
– tools/import_export
– tools/logs
– tools/sys_info
– tools/reset
– settings
– licensing
– upsell
– lorem
– logging
– i18n
– twig
– parsedown
– polylang_compat

ACTIVE PLUGINS:

WP RSS Aggregator: 4.17.3

DEACTIVATED PLUGINS:

Akismet Anti-Spam: 4.1.2
Hello Dolly: 1.7.2

CURRENT THEME:

Twenty Seventeen: 2.2

SETTINGS:

wprss_db_version 16
wprss_did_intro 1
wprss_intro_feed_id 8
wprss_intro_shortcode_page 7
wprss_prev_update_page_version 4.17.3
[wprss_settings_general]: Array
(
[open_dd] => blank
[follow_dd] => no_follow
[feed_limit] => 15
[date_format] => Y-m-d
[limit_feed_items_db] => 200
[cron_interval] => hourly
[styles_disable] => 0
[title_link] => 1
[title_limit] =>
[source_enable] => 1
[text_preceding_source] => Source:
[date_enable] => 1
[text_preceding_date] => Published on
[limit_feed_items_imported] => 0
[custom_feed_url] => wprss
[custom_feed_limit] =>
[source_link] => 0
[video_link] => false
[limit_feed_items_age] =>
[limit_feed_items_age_unit] => days
[time_ago_format_enable] => 0
[tracking] => 0
[custom_feed_title] => Latest imported feed items on WordPress
[pagination] => default
[authors_enable] => 0
[unique_titles] => 0
[expiration_notice_period] => 2 weeks
[feed_request_useragent] => Mozilla/5.0 (Linux 10.0; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36
[certificate-path] => wp-includes/certificates/ca-bundle.crt
[limit_feed_items_per_import] =>
[feed_items_import_order] => latest
[custom_css] =>
[html_classes] =>
[feed_cache_enabled] => 0
[schedule_future_items] => 0
)

PHP EXTENSIONS:

– Core
– PDO
– Phar
– Reflection
– SPL
– SimpleXML
– Zend OPcache
– bcmath
– bz2
– calendar
– cgi-fcgi
– ctype
– curl
– date
– dba
– dom
– ereg
– exif
– fileinfo
– filter
– ftp
– gd
– gettext
– hash
– iconv
– imap
– intl
– json
– libxml
– lzf
– mailparse
– mbstring
– mcrypt
– mysql
– mysqli
– openssl
– pcntl
– pcre
– pdo_mysql
– pdo_sqlite
– posix
– session
– soap
– sockets
– sqlite3
– standard
– tidy
– tokenizer
– xml
– xmlreader
– xmlrpc
– xmlwriter
– xsl
– zip
– zlib

### End System Info ###

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