Emails sent via Gmail sending BCC list to BTmail addresses gets corrupted

[knotts456]

I have a Windows 11 HP laptop with Norton 360 and MS Outlook. There have been no changes to my system but now when I send Emails via Gmail accounts using BCC to send a list of BTmail addresses the emails gets corrupted, stripping the 'from' and 'to' and ‘subject’ data and displaying the email as a string of text. Within the text is my message but most is format information.
All other non BT addresses receive the email correctly. I have copied the BT addresses to a separate list and emailed them using BCC from my BT email address and they receive the email correctly. I have tried sending via two different Gmail addresses and corruption occurs with both.
Any ideas how I can sort this as I have been using the BCC list from Gmail to BTmail forwarding for years without this problem so it's only just started to go wrong. I've made no changes to my system so what has happened? Your help will be much appreciated.

[licquorice]

There is a long thread here detailing the same problem. I have thought it was probably when Bcc was used to send to a group that the problem occurred but strangely message 30 in the thread seems to imply sending Bcc solves the problem.

I send to a group of Bcc recipients (including my btinternet address) using a Gmail address via Outlook 2010 and that works ok so it doesn't appear to be a universal problem.

[knotts456]

Thanks but it sounds like it could be a BT problem as one reply says BT have sorted her problem. Do you have a good contact at BT who I can message with my problem?

Thanks

[licquorice]

Its definitely a BT problem but doesn't appear to be universal.

I'll flag it to the mods for attention.

[knotts456]

Thanks licquorice

I'll await their response.

[Stevepmob]

What we are also seeing is when sending to a bcc group from a gmail account the btinternet recipients see txt within the mail  saying  ‘this message  is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible.’ 

sending same mail directly to the  user shows fine and appears happy the mail reader does support MIME 1.0 

doesn’t happen to any other mail recipients. 

[Ali_A]

 Hi @knotts456 

Welcome to the BT Community

For this one please can you call through to our Service Helpdesk so this can be escalated. 
Our team in the Copernicus team Level 2 will look into the cause and resolve. 

Thanks 

Ali

[knotts456]

Thanks Ali I give them a go

[Mogman]

I have just posted the exact same problem. Have you made any progress?

[licquorice]

@Mogman  Have you not seen my update to your thread?