I've been using Thunderbird for a very long time, supporting it's development with modest contribution. Until recently everything went smoothly when sending a message (I use 2 email accounts). However since a couple of weeks, there seems to be a delay when ever I send an email. Usually I was able to send a mail and keep working through my other mails. But this seems not to be the case anymore; Once I've clicked on sent (which is instant) I wanna to work/read other emails a message appears (TB does not reply anymore) and then only 5 seconds later I can keep scrooling through my list. It's strange. Any idea where this comes from. Many thanks for your answers. Stefan