Try manually resetting your plugins (no Dashboard access required). If that resolves the issue, reactivate each one individually until you find the cause.
If that does not resolve the issue, 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), navigate to /wp-content/themes/ and rename the directory of your currently active theme. This will force the default theme to activate and hopefully rule-out a theme-specific issue (theme functions can interfere like plugins).
@testopoho Did you try to debug the error.
The same thing happened to me because my update of WordPress has not completed correctly so I updated it through Cpanel and the error flew away.
Yes I checked its error from json extentsion which need to enable and im using vps where json is already enable on apache but im using litespeed where showing json is not enable
Thanks for resply