There's a handful of issues arising from last weekend's work (surprised how few there are).

Firstly, our workhorse system IS still emailing messages out. But as it's now a backroom system and not known as "firstgreatwestern.info", various intermediate email relays are a bit worried about it ...
* Client host rejected: cannot find your hostname
* refused to talk to me: 550 Message rejected
* Connection refused
OK - something to work on.  At the weekend?

Second, the workhorse system has for some time had traps in there to row back if it gets silly numbers of requests from a single place. I have had to lift the definition of a "silly" number since nearly all requests are now coming from the receptionist server; ealier today it was screwed down a bit hard and members were being directed to the status server far too often.

Third, our shift from http to https has been noticed by crawlers such as Google. Good, indeed excellent as is means that they are reporting us in searches with an increase prominence.  However, to do so they have been downloading pages with some vigour to ensure they know all about us.  The initial shock in now over - however as I bring in more older resources and new ones [back] online (flows, maps, geolocation, etc) thes is atill going to be the odd load issue.  My monitoting code usually spots problems and lets me know, but that's not instant and there will be occasions where a broad and expensive resource is being indexing and it may cause an issue for a few hours. I DO have plenty of resource with the receptionist and if need be a lot of the public content can be served from there.

Fourth reported:
That was only a warning and you can ignore it.  And I have told the server to now even tell you in the future.  It is / was caused by two visitors at exactly the same time trying to move a log file out of the way - the first succeeds and the second has been grumbling.

Also ... aware of the like system not echoing back in the page, the forum site style not being remembered, and acronyms not being expanded properly.  Searching and the easy access to our industry document archive need a look / check too.

Yep, I know.  We're sending them out but they're not being accepted.  Your email host is a fussy one and even before it gets to your email system it is almost certainly being refused.

Ha - the 'unlike' button seems (marginally) better, in that it opens a new window to display a blank page containing '*', and the discussion window is updated. Presumably the like/unlike behaviour should be similar, in terms of opening windows?

I've never had any notifications, despite being subscribed to various Subjects I've posted in and the TransWilts Board. Have I got the same problem as GBM?

In my Profile / Notifications and Email, the top 3 settings are ticked, and the dropdown is set to 'Replies and moderation'.

yes - that was probably to do with this:

Just noticed on the ‘look and feel’ selections, there’s some sort of artefact following the selected options about:

I reluctantly gave up on the struggle recently and started using a third-party host to send transactional mails. I use Amazon's SES, which allegedly stands for "Simple Email Service" though nothing with AWS^▸ (Automatic Warning System) is ever simple. But it works and the emails get delivered, which means I no longer have to answer queries about "my registration email hasn't arrived, how do I log in". There are lots of alternatives which tend to be easier to set up, but at a higher per-email cost.

https://www.mail-tester.com is really good for diagnosing mail deliverability issues though not foolproof.

edit: AWS in this case isn't Automatic Warning System (prevents SPADs^▸ (Signal Passed At Danger) aka Signals Passed At Danger) but Amazon Web Services (prevents SPADs aka Server Panics And Dies).