CFP3 & Thunderbird uploads

I note some earlier problems with V2 & TBird on the help forum … I am having similar problems since installing CFP3. Any outgoing emails with attachments over about 500kb will stall and give an error message relating to checking SMTP settings. At first I thought it may relate to Avast AV which I had also recently installed, but temporarily disabling CFP seems to be the fix. Tbird & Firefox are both allowed in the CFP Security settings. What other settings should I be checking??
Ta
Bazzaw

What OS/CFP3 version? What are your network security policies for ashmaisv.exe? Both TB and ashmaisv should be set as email clients.

OS is XP Pro, CFP version is 3.0.21.329. Avast Network policies are Normal and for Internet Mail I have turned off SMTP scan, just scanning incoming mail.
Thanks

What is your Comodo Network Security Policy for Thunderbird?

Sorry about the delay … the NSP for Tbird is as shown in the attached Snagit file - basically Custom, Allow All as it is for most other programs.

[attachment deleted by admin]

Why don’t you try making Thunderbird an email client from the pull down menu of predefined policy’s.

OK - done. Hadn’t delved to that level of CFP yet, so still on a learning curve. Guess I need to check same for other programmes!
Ta for the help
B

Did it work? (CLY)

Seems to be working - a bit of hesitation before confirming email sent with a 1Mb attachment, but it went OK. Cheers.

Your welcome. Be sure to make IE and FF browsers under Network Security Policy.

Will do - and Filezilla presumably an FTP client …
Chz