Undefined index encrypter.php after admin login in magento 2

Question

1 exception(s): Exception #0 (Exception): Notice: Undefined offset: 2 in /var/www/html/Registration/vendor/magento/framework/Encryption/Encryptor.php on line 588

• Shoaib Munir: what is your php version?
• Harsh Jayswal: Is that comes after upgrading or after installation of new Magento? Which Magento version you are using?
• usman: @ShoaibMunir php version is 7.2
• usman: @HarshJayswal i am using magento 2.3. i am working on Extension devolpment. when i install magento 2.3 everything is working fine. but now admin login is not working but admin login page is displayed but when i enter login credential it gave me exception of undefined index .i have also tried it on php version 7.1 but facing the same exception

Answer 1

ok got your problem just create a new admin user using the following command

bin/magento admin:user:create

after that login with new admin id it will solve your problem.

• usman: it does not solve my problem
• Waqar Ali: i have Migrated My Site from Magneto Cloud to AWS Server and this Solution Helped me Thank You

Answer 2

Your environment is using ARGON2ID13 instead of SHA256 for hashing.

Check if you have 'sodium' php extension enabled.

If you disable the libsodium php extension, it will fallback on SHA-256 and won't break Magento.

In the Docker php-fpm image you can comment it out in /usr/local/etc/php/conf.d/docker-php-ext-sodium.ini:

;extension=sodium.so

• usman: the senerio is i devolped extension on magento 2.3 and for testing of extension i insall magento 2.2.9 and extension behave excellent but after tesing when i want to login on magento 2.3 admin pannel it gave me this exception.does it resolved by installing sodium extension?
• Shoaib Munir: not install, you need to disable sodium extension
• Shoaib Munir: Check this one: github.com/magento/magento2/issues/23511#issuecomment-507033705
• usman: How to check this extension is enable?
• usman: i have read this issue on provided link but here only describe its a PHP version issue but its not a PHP issue because i have have checked it by change PHP version