Invalid Form Key. Please refresh the page. on magento admin login page

I have a weird situation again that I have encountered on Magento. A few hours ago, I successfully logged in to admin dashboard. After I logged out and restart my pc and tried to log in again. I got an error

> Invalid Form Key. Please refresh the page.

Magento was installed on a live server. I didn't change anything or add something to the database. Credentials are valid but we cannot log in. Also, I cannot login to the Magento downloader panel.

What kind of bug is this?

How can we solve this?

**UPDATE!**

From @DouglasRadburn link. The detailed explanation of the problem and the possible solutions.

>

[To see links please register here]

Also similar to @Makwana Ketan answer

Please ask hosting provider to increase php_value `max_input_vars 75000`.

I am sure that problems came from session storage & cookie setting.

You should follow below:

DELETE FROM core_config_data WHERE path='web/cookie/cookie_domain';

DELETE FROM core_config_data WHERE path='web/cookie/cookie_path';

Delete all directories from below folders:

/var/session
/var/cache

***While working on localhost can not sign in or create Account - ubuntu OS***

> Invalid Form Key. Please refresh the page.

**invalid key error solve**


> change this value in your php.ini file

max_input_time : 3600
max_input_vars : 200000
memory_limit : 2G

>*then go to your MySQL database*

find core_config_data table

**change base URL localhost to 127.0.0.1**

than **search** path Like %...% domain then Go

**change** value *localhost* to *127.0.0.1* in front of *web/cookie/cookie_domain* ( path )

>Go to your magento root directory
then app -> /etc/ -> env.php open this file
change value localhost to 127.0.0.1 ( 2 places in file )

*go to browser press <kbd>ctrl</kbd>+<kbd>shift</kbd>+<kbd>delete</kbd> then check cache || cookie click on **clear data***

> then run all command with sudo on magento root directory

php bin/magento setup:upgrade

php bin/magento setup:di:compile

php bin/magento setup:static-content:deploy -f

php bin/magento indexer:reindex

php bin/magento cache:clean

php bin/magento cache:flush

In my case, I was having this issue in my localhost after using production DB. I tried setting up max_input_vars but that didn't work. But clearing cookie settings such cookie path and domain works. So, go to stores -> configuration then General —> Web —> Default Cookie settings and remove values for cookie path and domain. Then clear magento2 configuration cache using bin/magento cache:clean config. This should resolve it.

Open your Browser, Clear cookies and session data. for safety clear your cache by `bin/magento c:c`, then refresh the browser page.

If the db is copied from the other server, just create a new admin user. The issue will resolve