@Jan20191 if other activities are running normally the issue is unlikely to be difrectly related to your Sky Broadband connection. A lot depends on the mail programme you use and the email provider. For example I had a similar issue which I traced to an issue with the mail app on my iPad and the privacy settings in ios stopping my gmail messages opening properly.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
