Multiport message in MIME format

[awr10e]

Hi

I keep receiving emails in Multiport message in MIME format which are full of gibberish and doesn't include any attachments.

They only come from one sender using Gmail but only when they send me email to several recipients, if they send just to me the email is fine.

Any advice or fix would be great 

Thanks 

[awr10e]

Further more. Was speaking to my dad and the same thing is happening when receiving group emails from Gmail 

So I can only conclude it's a BT email server issue.