Unfortunately, because forum settings, server settings, other host variables, together with members' ISPs, devices, browsers and associated settings, individually or in combination can all be implicated, it's a very hard one to work on, especially as I've been unable to replicate it on any of my devices. All I can do is read up on the many trouble shooting attempts by other users of the software and see by trial and error if anything applies.
I've made one change to my settings and will await feedback. Please delete cookies and cache (as usual) before telling me that nothing's changed.
Dutchboy - email me
your advert and I'll put it up.