I have installed magento 2.4 on windows 10 and wampserver. It is installed now. I can't login to backend. I does not through any error notification either. enter image description here

While front end login and create customer is also not working. It show invalid form key always. enter image description here

2 Answers 2


I Found the issue! In Magento 2.4.5-p1 it seems that a value of "0" for "Max Session Size in Admin" breaks it. In normal behaviour "0" should disable the size. I set mine now to "2560000" cause the default setting of "256000" isn't working for us (too low) and that solved this issue for now.

You can set it to this value through CLI (flush cache after):

bin/magento config:set system/security/max_session_size_admin 2560000

I checked deploy mode with this command

php bin/magento deploy:mode:show

Deployment mode was "default". I changed the deployment mode from default to developer and its start working.

 bin/magento deploy:mode:set developer

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