Wordpress Widget Error after White Screen of Death

Question

Specification:

• Wordpress 5.5.1
• Divi Theme
• Php 7.4.11

1st Error (All pages not found)

• Frontend is accessible, but all the pages not found.
• Admin Panel is accessible except for pages (error 403)

What I did:

• Update Plugins (same error - pages not found)
• Disable Plugins via admin panel (same error - pages not found)
• Adjust Permalinks (same error - pages not found)
• Update Divi Theme - Parent Theme (same error - pages not found)
• Revert to Parent Theme (2nd error starts - white screen of death)

2nd Error (White Screen of Death)

• No error message
• Admin Panel not accessible
• Frontend and Backend - white screen

What I did:

• WP Debugger on
• Disable Plugin folder (same white screen)
• Disable Theme folder (same white screen)
• Check php version (tried changing it, same white screen)
• Disable Individual plugin folder (same white screen)
• Disable Individual theme folder (with error message)

Error Message from php_errorlog

[21-Oct-2020 03:00:51 UTC] PHP Fatal error:  Uncaught ArgumentCountError: array_merge() does not accept unknown named parameters in /my-site/wp-includes/widgets.php:1265
Stack trace:
#0 /my-site/wp-includes/widgets.php(1265): array_merge(wp_inactive_widgets: Array, sidebar-1: Array, sidebar-2: Array, sidebar-3: Array, sidebar-4: Array, sidebar-5: Array, sidebar-6: Array, sidebar-7: Array)
#1 /my-site/wp-includes/widgets.php(1220): retrieve_widgets(true)
#2 /my-site/wp-includes/class-wp-hook.php(289): _wp_sidebars_changed('Site Name')
#3 /my-site/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#4 /my-site/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#5 /my-site/wp-includes/theme.php(3267): do_action('after_switch_th...', 'Site Name', Object(WP_Theme))
#6 /my-site/wp-includes/class-wp-hook.php(287): check_theme_switched('')
#7 /my-site/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#8 /my-site/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#9 /my-site/wp-settings.php(546): do_action('init')
#10 /my-site/wp-config.php(80): require_once('/directory/...')
#11 /my-site/wp-load.php(37): require_once('/directory/...')
#12 /my-site/wp-blog-header.php(13): require_once('/directory/...')
#13 /my-site/index.php(17): require('/directory/...')
#14 {main}
  thrown in /my-site/wp-includes/widgets.php on line 1265

Answer 1

Solved!

Commented out this line on htaccess

AddHandler application/x-httpd-php80 .php .php5 .php4 .php3

and disabled some plugin like goodbye-captcha

everything works fine again