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Issue WP Toolkit, unable to log in to Wordpress Backend (500 Header Values must me RFC 7230 compatible strings)

fpanzer

New Pleskian
Server operating system version
Ubuntu 24.04
Plesk version and microupdate number
Plesk Obsidian 18.0.77 Update 4 Web Host Edition
When using the login button for a wp-toolkit enabled Wordpress Instance

i get a new tab where it says
"Anmeldeinformationen des WordPress-Administrators werden abgerufen. Bitte warten...", then after a few seconds i get

{"meta":{"status":500,"message":"Interner Serverfehler: Header values must be RFC 7230 compatible strings"}}

Plugins, Themes etc. can be retreived from the wordpress instance without any problem.
Directly logging in to domain.tld/wp-admin works.

Any advice, anyone?
 

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@Francesco Dalla M , could you please confirm if WP-Toolkit is the latest version 6.11.0-10571 (Plesk panel > Extensions > My extensions)? If yes, please double-check what's being logged in /var/log/plesk/panel.log at the time of the error occurrence.
 
It might not be related to the WP Toolkit, but to a plugin or theme of the website. I've seen the symptom several times in customer installations that were using problematic plugins. Have you tried to login using the /wp-login.php page?
 
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