Can’t login after enabling object cache

Ok, just got this email:

An error of type E_ERROR was caused in line 215 of the file /var/www/html/domain/public_html/wp-content/plugins/redis-cache/redis-cache.php. Error message: Uncaught Error: Call to undefined method WP_Object_Cache::redis_status() in /var/www/html/domain/public_html/wp-content/plugins/redis-cache/redis-cache.php:215
Stack trace:
#0 /var/www/html/domain/public_html/wp-content/plugins/redis-cache/redis-cache.php(193): RedisObjectCache->get_redis_status()
#1 /var/www/html/domain/public_html/wp-content/plugins/redis-cache/includes/admin-page.php(42): RedisObjectCache->get_status()
#2 /var/www/html/domain/public_html/wp-content/plugins/redis-cache/redis-cache.php(105): require_once('/var/www/html/w...')
#3 /var/www/html/domain/public_html/wp-includes/class-wp-hook.php(287): RedisObjectCache->show_admin_page()
#4 /var/www/html/domain/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters()
#5 /var/www/html/domain/public_html/wp-includes/plugin.php(478): WP_Hook->do_action()
#6 /var/www/html/domain/public_html/wp-admin/admin.php(254): do_action()
#7 /va

• This reply was modified 5 years, 10 months ago by dcivera.

Sorry, nothing is working.

I did all the steps you mentioned, deactivated the plugin, flushed the cache with wp-cli. Then reactivated it. Still the same issue.

I tried to set WP_REDIS_HOST in wp-config. I set it to 127.0.0.0 and localhost, but it’s the same.

I also set maxmemory 128mb and maxmemory-policy allkeys-lfu in ~redis.conf` for good measure.

I ran monitor in redis-cli and I see the plugin working. I see the object-cache.php (I didn’t realize the file got deleted when you disabled object cache). When I run info keyspace, I see the DB, but for the life of me I can’t figure out why the WP admin gets stuck. I enter my user name and password, press submit and it shows the login screen again.

• This reply was modified 5 years, 10 months ago by dcivera.
• This reply was modified 5 years, 10 months ago by dcivera.
• This reply was modified 5 years, 10 months ago by dcivera.

As I mentioned, I can’t log into WordPress once the plugin is activated. I get to the login screen, enter my user name and password, and instead of logging me in, it presents the login screen again.

The problem goes away when I Disable Object Cache.

Additionally, when I Enable Object Cache and the plugin connects to Redis, I can’t flush the cache. When I press the button, it tells me there was an error. Similarly, I can’t use wp-cli to flush the cache or disable redis-cache. It also throws Error: Object cache could not be disabled.

• This reply was modified 5 years, 10 months ago by dcivera.

127.0.0.1:6379> flushall
OK
127.0.0.1:6379> dbsize
(integer) 0
127.0.0.1:6379> 

When I click Enable Object Cache

1. I see

Status: Connected
Client: PhpRedis (v5.1.1)
Key Prefix: wlikjwe9812wklj

I also attached a copy of the diagnostic at the end of this message

2. The WordPress login screen is no longer working. When I enter my username and password and press enter, instead of loging me in, it asks me to enter my username and password again.

3. When I press the Flush Cache button, I see Object cache could not be flushed.

4. When I press Disable Object Cache the WordPress login screen is usable again.

Status: Connected
Client: PhpRedis (v5.1.1)
Drop-in: Valid
Ping: 1
Redis Extension: 5.1.1
Predis Client: 1.1.1
PHP Version: 7.4.3
Redis Version: 5.0.7
Multisite: No
Global Prefix: "dlkd90ldsf_"
Blog Prefix: "dlkd90ldsf_"
WP_REDIS_HOST: "127.0.0.1"
WP_REDIS_DATABASE: 1
WP_CACHE_KEY_SALT: "wlikjwe9812wklj"
WP_REDIS_PASSWORD: "****************************************************************"
Global Groups: {
    "0": "blog-details",
    "1": "blog-id-cache",
    "2": "blog-lookup",
    "3": "global-posts",
    "4": "networks",
    "5": "rss",
    "6": "sites",
    "7": "site-details",
    "8": "site-lookup",
    "9": "site-options",
    "10": "site-transient",
    "11": "users",
    "12": "useremail",
    "13": "userlogins",
    "14": "usermeta",
    "15": "user_meta",
    "16": "userslugs",
    "33": "blog_meta"
}
Ignored Groups: [
    "counts",
    "plugins",
    "themes"
]
Unflushable Groups: []
Dropins: 
 - advanced-cache.php v by 
 - Redis Object Cache Drop-In v1.5.9 by Till Krüss
Plugins: 
 - Akismet Anti-Spam v4.1.5 by Automattic (Active)
 - AMP v1.5.3 by AMP Project Contributors (Active)
 - Classic Editor v1.5 by WordPress Contributors (Active)
 - Convert Plus v3.5.8 by Brainstorm Force (Active)
 - Health Check & Troubleshooting v1.4.4 by The WordPress.org community (Active)
 - Hello Dolly v1.7.2 by Matt Mullenweg (Active)
 - Inactive Logout v1.9.5 by Deepen Bajracharya (Inactive)
 - Redis Object Cache v1.5.9 by Till Krüss (Active)
 - ShortPixel Image Optimizer v4.18.0 by ShortPixel (Inactive)
 - Simple History v2.33.2 by Pär Thernström (Active)
 - Slider Revolution v6.2.8 by ThemePunch (Active)
 - Supreme Shortcodes v2.0.1 by Supreme Factory (Inactive)
 - tagDiv Cloud Library v1.5 | built on 06.05.2020 14:38 by tagDiv (Active)
 - tagDiv Composer v2.6 | built on 06.05.2020 14:38 by tagDiv (Active)
 - tagDiv Mobile Theme v1.4 | built on 06.05.2020 14:38 by tagDiv (Active)
 - tagDiv Newsletter v1.5 | built on 06.05.2020 14:38 by tagDiv (Active)
 - tagDiv Social Counter v4.7 | built on 06.05.2020 14:38 by tagDiv (Active)
 - tagDiv Standard Pack v1.0 BETA | built on 06.05.2020 14:38 by tagDiv (Active)
 - Two Factor Authentication v1.7.2 by David Nutbourne + David Anderson, original plugin by Oskar Hane (Inactive)
 - WordPress RSS Feed Retriever v1.6.1 by Theme Mason (Active)
 - WPBakery Page Builder v6.2.0 by Michael M - WPBakery.com (Active)
 - WP fail2ban (Premium) v4.2.8 by Charles Lecklider (Inactive)
 - WP Rocket v3.5.5.1 by WP Media (Active)
 - WP Security Audit Log v4.0.3 by WP White Security (Active)
 - Yoast SEO v14.1 by Team Yoast (Inactive)

Just tried it and nothing. Cleared all cache and cookies from the browser. Set WP_REDIS_DATABASE=8. I also added WP_REDIS_SELECTIVE_FLUSH=true (it wasn’t set before), but that didn’t do anything either, so I removed it.

Thank you so much for sticking with me on this. I’m sure I must be an edge case, so I greatly appreciated it.

Just one thought, could the fact that the domain isn’t publically available cause the issue? It’s a staging server at the moment, so /etc/hosts on my machine and the server’s is pointing the server’s IP. I don’t see why, but I’m at a loss.

Thanks again for your help.

P.S I’m encountering the issue on Safari, Chrome, and Firefox

• This reply was modified 5 years, 10 months ago by dcivera.
• This reply was modified 5 years, 10 months ago by dcivera.

Thanks again for your perseverance.

Before contacting you, I had enabled troubleshooting mode, but after your suggestion, I manually deactivated all plugins, but unfortunately, the issue is still there.

Should I try to remove the SSL certificate and Certbot?