I am unable to login to customer account it is giving error 'an unspecified error occurred please contact us for assistance'. I have checked my customer_entity table has columns 'failures_num' and 'first_failure'. Still the issue is there.
You can check error. Go to file vendor/magento/module-customer/Controller/Account/LoginPost.php and put these lines
$message = $e->getMessage(); $this->messageManager->addError($message);
just before lines-
$this->messageManager->addError( __('An unspecified error occurred. Please contact us for assistance.') );
now on front try to login and check error.