Here we go:
Pie Register Version
Pie Register (Base) 3.0.8
PHP Version
5.6.33-0+deb8u1
MySQL Version
5.5.5
Wordpress Version
4.9.4
Curl
Enable
File Get Contents
Enable
MB String
Enable
PHP Post Max Size
64M
PHP Time Limit
300
WP Memory Limit
10M
WP Debug Mode
No
WP Language
de_DE
WP Max Upload Size
64 MB
================= Themes =================
Graphene [ACTIVATED]
================= Plugins (45/47) =================
Add Headers [ACTIVATED]
Advanced Access Manager [ACTIVATED]
AMP [ACTIVATED]
Autoptimize [ACTIVATED]
BackWPup [ACTIVATED]
Breadcrumb NavXT [ACTIVATED]
Category Sticky Post [ACTIVATED]
CiviCRM [DEACTIVATED]
Custom Menu Wizard [ACTIVATED]
Duplicate Post [ACTIVATED]
Easy WP SMTP [ACTIVATED]
Enable Media Replace [ACTIVATED]
EU Cookie Law [ACTIVATED]
Far Future Expiration Plugin [ACTIVATED]
Fix Structured Data Errors [DEACTIVATED]
Glue for Yoast SEO & AMP [ACTIVATED]
Google Authenticator [ACTIVATED]
Google Authenticator - Per User Prompt [ACTIVATED]
Improved Save Button [ACTIVATED]
Login Logout Register Menu [ACTIVATED]
Menu Items Visibility Control [ACTIVATED]
Nav Menu Roles [ACTIVATED]
Page-list [ACTIVATED]
Peter's Collaboration E-mails [ACTIVATED]
Pie Register (Base) [ACTIVATED]
Post Expirator [ACTIVATED]
RankYa Fix hatom Errors [ACTIVATED]
Redirection [ACTIVATED]
Remove Author Pages [ACTIVATED]
Remove Query Strings From Static Resources [ACTIVATED]
Restrict Content [ACTIVATED]
Shariff Wrapper [ACTIVATED]
Simple Page Ordering [ACTIVATED]
Statify [ACTIVATED]
The Events Calendar [ACTIVATED]
TinyMCE Advanced [ACTIVATED]
User Switching [ACTIVATED]
Wordfence Security [ACTIVATED]
WordPress Force HTTPS [ACTIVATED]
WordPress phpinfo() [ACTIVATED]
WP-Filebase [ACTIVATED]
WP Author Slug [ACTIVATED]
WP Content Security Policy Plugin [ACTIVATED]
WP Mailto Links - Manage Email Links [ACTIVATED]
WP SEO Structured Data Schema [ACTIVATED]
WP User Avatar [ACTIVATED]
Yoast SEO [ACTIVATED]Nav Menu roles was added to solve the problem, it has no effect on the problem.
Error log is empty.
Thanks,
Andreas