Cant activate plugins

my wordpress cannot update to 4.9

Are you trying auto updating or Manual updating?

If your server does not like auto updating, try MANUALLY updating. Download WordPress again and unzip it. Access your server via SFTP or FTP, or a file manager in your hosting account’s control panel (consult your hosting provider’s documentation for specifics on these), and delete then replace your copies of everything on the server except the wp-config.php file and the /wp-content/ directory with fresh copies from the download. This will effectively replace all of your core files without damaging your content and settings. Please read the Manual Update directions first.

nor activate installed plugins

First, try finishing WordPress update.

• This reply was modified 7 years, 3 months ago by t-p.
• This reply was modified 7 years, 3 months ago by t-p.

Same for me.

It kinda updates but whats new page says its 4.8.3 and suggests again to update to 4.9.
Manually replace files but it still says there is update available to 4.9.

Admin user cant activate or deactivate any plugin.

Side note to @edzuslv,

please do not jump into other topics. If the troubleshooting already posted made no difference for you, then, as per the Forum Welcome, please post your own topic. That way you stand a good chance of getting the assistance you want. Despite any similarity in symptoms, your issue is likely to be completely different because of possible differences in physical servers, accounts, hosts, plugins, theme, configurations, etc. Thus one problem, on one setup is not indicative of the functionality and reliability of an application as a whole.