Sorry for the much belated reply. :-) The mail problem above has now been resolved as we eventually updated the template to the latest version (2.0.1) and, somehow, that fixed it and that part is fine now, so we won't have to use SMTP after all.
However, updating the template has caused another (much more visually damaging) issue; all bullet points and social share icons have now been replaced by small boxes with question marks inside them - in certain browsers. The problem is visible in MSIE, MSEdge, Chrome and Brave browsers .. but strangely enough not in Firefox?
Please see screenshots: -
I have so far not been able to determine what causing this. I have been using the inspector tool to try and locate the problem - and after playing around with font settings a lot it appears not to be font-related but it's still unclear exactly what the problem is. I have tried using other font families than FontAwesome and so on but to no avail.
To make sure it isn't a local / device issue, I have also checked on a separate laptop running MSEdge which has never visited the website before - and the problem is visible. On two Android mobile devices both using Brave browser there is no problem, also after clearing cache, etc. on both devices. So - the problem is definitely real but it doesn't show on every device / every browser.
Further to that I have extracted the complete template.css file from a backup made weeks ago, long prior to updating the template which I did yesterday and, as a test, replaced the entire template.css contents with that of the backup which I know was working fine - also without any success. So I'm stumped.
I have no idea what is causing this as I don't know what controls these bullet points and social icons, if it's not something within the CSS? And as I wouldn't know what to look for, I really hope you can help - this looks really bad on the site! :-(
Thank you very much in advance!