A 'padlock' has appeared on 'the envelope' on my email account so I cannot access previous mail - help!
The problem is there across all my devices. I can receive new emails through the account - but not historical ones. Apart from new emails there is nothing in my inbox which should contain c. 100 emails. I mention the 'padlock' as that icon is not on my other e-mail accounts and I've never seen it before.
ప్రత్యుత్తరాలన్నీ (1)
The lock icon indicates that the account uses a secure connection and would have been there since you configured the account that way. It has nothing to do with the account being locked. If you look at the address bar in your Internet browser you will see the same lock icon when using a secure site. Check under your View options and make sure Threads are set to ALL. If set to Unread then as soon as you read an email is would be hidden.
After that I am not sure what would be hiding your old messages.