I have an ongoing issue with my BT Full Fibre setup. I have several domains and associated email addresses which are hosted by one of the large web hosting companies.
When using Mac Mail on any of my Apple devices (MacBook Pro, Desktop, iPad, iPhone etc Mac Mail continually reports that the SMTP servers are offline. Trying to change any server settings in Mac Mail is also almost impossible as the username and password can't be verified due them being offline. I have also tried using Thunderbird mail client with the same result.
Switching to 4g and sending from my phone or using webmail works fine proving the servers are not offline and all settings are correct i.e. port 465 SSL Password etc. and effectively means my hosting company is off the hook.
Switching the BT Home Hub off and leaving it off for sometime often results in the problem being resolved but only for a short time - sometimes a few hours, sometimes a few days. I am making the assumption that the newly assigned IP address is solving the issue. I have even managed to get a new router sent out and the problem was resolved for nearly two weeks!
Could it be that BT or the router is blocking my outgoing emails or blocking port 465? It has proved impossible to get bt to look into this for me as they simply state they do not support 3rd party email addresses or it's my hosting company's problem blah blah blah which is of course a complete cop out. I have also ran multiple scans for malware and virus all with negative results. As an aside my wife also has the same issues on her devices albeit with the same domains. Any suggestions gratefully received before I throw the towel in and change to a different ISP? Many thanks