Password reset token email not received

We have been successfully using PHPList for over two years and two months ago we moved the application from our domain website into its own dedicated sub-domain, secured with an SSL Certificate. Everything has worked normally for two months until now when an Administrator tried to reset her password. The token sent success message appears on the Dashboard login web page but the token password reset email is not being generated/received. Any suggested solutions will be sincerely appreciated.

Have you checked that the email used to generate the password reset email is still valid?

Yes the email address used to generate the reset request is valid and operational.

I checked the config file, all the settings in PHPList and could not find any incorrect settings. Logged in today (a gap of two days after the initial problem) sent a password reset token request through the Dashboard and it’s all working perfectly. So the problem has gone away without being able to identify the cause.

I am experiencing the same problem…
no admin password can be updated

cannot add a new admin because it will not let me select a password
all of the campaigns are being saved in the active area rather than being finished

using phplist 3.3.3