Invalid Activation Code error message when authenticating users

Having installed a skin to redirect user registration confirmation requests to the administrator for approval (as per Manually_approving_registrations and Faq12) I was able to add one user, but for subsequent users I get the error message "Attention Invalid Activation code". After adding the first user, I was logged in as that user so I logged out and then in as admin (didn't help), then I closed the browser and tried again but I am still getting the error message. (Using the Template login manager and the HtPasswdUser password manager).

I am not sure how to get around this and add my new users, especially as they have already chosen a password. Thanks in advance for any suggestions!

-- JamesWhitby - 03 Jan 2013

Are you getting the same error code for every registration? (You should not - each registration should have a unique code).
Are there any errors logged either in your foswiki error log, or apache error log?
Check the contents of your working/registration_approvals/directory. There should be a file there that is created when the registration request is made. It is removed on two conditions
- User (or in your case admin) confirms the registration or
- $Foswiki::cfg{Sessions}{ExpireAfter} timer is exceeded.

-- GeorgeClark - 04 Jan 2013

I don't see an error code with the error message, just the text saying Attention Invalid activation Code. Each user has a different verification code that is repeated in the error message.
There was one error in the Foswiki log stating that a username was not a valid WikiWord (apparently later corrected by the user) and some errors stating that EmptyPlugin (apparently a module) could not be loaded. It seems that no entryin the error log is made for the failed registrations, nor in the event log. I'm on a hosted server and don't have access to the Apache error log file.
Your third point would seem to be the key - the expected files are not present in working/registration-approvals and it seems that the default {Sessions}{ExpireAfter} is 21600 s or six hours and that this is also the lifetime of a registration request. This is clearly too short if this is the lifetime of the registration requests and it takes a day or so to authorize the request. I have now made this a negative number, so will have to tackle the cron jobs next!

Problem solved, many thanks!

-- JamesWhitby - 04 Jan 2013