That’s odd. That message is not from Event Organiser. So unless it is from a another plug-in it would have to be this line: https://github.com/WordPress/WordPress/blob/df97f83cb63297a6d830f4daedd9ca1eba5e06f1/wp-includes/load.php#L224 (the only instance in WordPress that text appears).
That is triggered, under certain circumstances, if wp_maintenance() is called. But that is done so before any plug-ins are run.
In short, (and unless there’s another plug-in that could be displaying that text), it can only be your WordPress installation and/or server environment that is causing that message. Which does beg the question – why does it only appear for Event Organiser settings?
Somethings to check, (which you can see in wp_maintenance() ):
- Is there a
.maintenance file in the root of your install?
- If so, it should define a value for
$upgrading. What is it?
Apart from that, my only suggestion is to add some error logging (i.e. log the value of wp_debug_backtrace_summary() just above where the error message is called.
Ok, started debugging and magically started working.
Not sure what happened, but working again now.
Thanks