New User Activation email seny OK but no password login email

wp 4.4.3 (not 4.3.2 as displayed)

Why are you using an old copy of WordPress? Were you aware that your site is currently running a very real risk of being hacked? You need to upgrade WordPress asap.

Hi esmi – I am always a bit behind with version number as I find that everytime I upgrade wordpress I spend several hours/days fixing broken plugins… It’s one of my least favourite things about using WordPress (my second is identifying plugin conflicts!)

Do you have any information to suggest that updating to the latest WordPress will fix the problem I am experiencing?

Not directly, no but I have plenty of evidence that it will stop hackers targeting your site. Were you aware that they will often target sites that are “just one or two versions behind”?

Hey esmi thanks – I upgraded and the emails started working again! How about that…
The only thing that broke is that I can’t login as any user any more from here (though others don’t seem to be having that problem). I don’t have any ip blocking plugins installed so I dunno what might be doing that. Guess I’ll leave it for a bit and see if it starts working again…. If not I’ll need to figure it out.

What happens when you try to login?

working again now esmi – but it was just going back to the login page, with no comment… weird.
Thanks for your help ??

…oops I spoke too soon it’s not sending the password email again.
Damn
I’ll look again in the morning (I’m on UK time)

Weird – clearly working for some folks as I see someone has just signed up and activated their account and received both activation and login emails…
Just won’t send me that second email…
Ooops no I speak too soon again – now it won’t even activate! just sends me back to the login screen without any comment and no emails sent………………………..

This problem is still ongoing and I have no idea how to approach debugging it…
When I signup as a new user, I am sent the first activation email, but after activating the second email containing login details does not arrive.
If I manually add a new user and tick the box ‘Send the new user an email about their account’ again no email is sent.
I can confirm from the logs that the emails are not being sent.
I can’t do the standard refrain – change the theme and switch off all the plugins – as usual this would be entirely impractical (and probably lose half the content in the process) on a live, production site.
Any ideas at all? I am really struggling to find useful, live debugging methods for wordpress for a number of issues including this one – I just hit a brick wall. I have posted another general question on this topic here: https://www.ads-software.com/support/topic/debugging-wordpress-problems-strategies if you have any thoughts…