1. What mail provider is it? 2. What is the server name?

Have you tried disabling your anti virus email scanning component. Sounds like you might have an issue there as you can send it is unlikely to be your firewall, unless it is port blocking not application blocking.

Email server is called isp.com I haven't messed with any of the antivirus (Norton) stuff, because it was working just fine and nothing was changed to cause the hang up. [Warning: middle-aged housewife who isn't very tech savvy ... expect dumb questions.]

I don't see anything in the "spam filter" place for incoming or outgoing emails that is out of the norm (nothing in there for outgoing; only junk emails in the incoming box). I tried to check Norton for antivirus email blocking -- it does have a place with a check box (which is/was checked) to "protect against timeouts" -- for when it is scanning a large attachment, etc.

I called the isp.com people today and after confirming all the settings were right, they just said it wasn't on their end, probably something is changed with the Thunderbird update I did 2 weeks ago. In spite of the fact that it worked OK for most of the time between that and last Friday.

What everyone forgets is Nortons calls home every day, so it changes daily. Those "suddenly is does not work" issues are most often a problem with the anti virus.

Basically start by disabling Norton's email scanner. It does not work with most email accounts anyway. As ISP uses SSL in it's connections the Norton mail scanner will not work on the best day.

Setting here http://www.netfaqs.com//faqs/gsettings.asp?bisp=isp.com&theurl=http://www.isp.com

Thank you. I have changed the settings yesterday for isp to those you have linked (to pop.gmail.com) but it didn't help -- and when I called customer service, they confirmed that what I have had it set at all along (mail.isp.com) is the correct setting -- despite their own website saying otherwise. Maybe I should call them back tomorrow and point this out. I have no add-ons in Thunderbird (deleted the one I did have yesterday).

So for now I have turned off the Norton email antivirus scan (Norton complaining loudly that this is not good), and changed the incoming email server setting to pop.gmail.com in Thunderbird. "Connected to pop.gmail.com ..." and then it waits quite a while before the time out message, "Connection to server pop.gmail.com timed out." I think I'll try turning off the computer and restarting with these changes next to see if that makes a difference.

Using the pop.gmail.com setting made it ask for a password, which it then said "user name and password are not accepted."

After trying several different settings over 2 weeks to try to get my emails off the server to Thunderbird (and hoping it might fix itself, which it didn't), this morning we had a breakthrough. I disabled the "smart firewall" on the Norton Internet Security program for 15 minutes and tried to connect Thunderbird. It asked for a password and on the third try I entered the right one (this is the problem with passwords!) and in came 170 emails. So at least, I figured, I could check my emails by turning off the firewall a few times a day for a short time -- but when the 15 minutes expired, Thunderbird is still able to check for incoming emails.... Problem solved, but I'm not quite sure exactly how... but it was a Norton vs Thunderbird issue, we at least know that.

AAanannnd, now it won't SEND emails... asks for my password, but won't accept it. Grr.

Nortons does a great job of messing with all mail programs. It does tend to leave Outlook alone. Perhaps they actually test against that one. But the norton Firewall, the Sonar and the mail scanner are all problematical.

Every minor bump in the Thunderbird version from the 6 weekly updates leads, or often leads, to the program being blocked from accessing the internet by the firewall.

The sonar makes the new account wizard fail in 90% of cases and the email scanner only works in non SSL/TLS protected email accounts. Again almost all mail accounts.

So, all in all, a great product if all you do is surf the web using a web browser. I constant maintenance and tweaking point if you actually use programs that are not a browser. I suggest you contact the Norton Tech people and ask them what is wrong with Nortons.

Having time-out issues with a yahoo account as well, but I'm unable to post a request for help in this forum.

In my case, I set up a new profile. The email connection is working with my existing default profile, but not for the new profile I set up.

Not sure how to post here. I type my issue, here in the forum, click on send and nothing happens. I tried FF Accounts and couldn't get into the forum at all. I don't want anything forum related on my phone, so I can't get past the verification process. When I do a search for my own posts here in this forum, it says none are found, even though I just posted a couple of weeks ago.

Foxhunt said

Having time-out issues with a yahoo account as well, but I'm unable to post a request for help in this forum. In my case, I set up a new profile. The email connection is working with my existing default profile, but not for the new profile I set up. Not sure how to post here. I type my issue, here in the forum, click on send and nothing happens. I tried FF Accounts and couldn't get into the forum at all. I don't want anything forum related on my phone, so I can't get past the verification process. When I do a search for my own posts here in this forum, it says none are found, even though I just posted a couple of weeks ago.

If you can post into someone else's topic, you can post your own. Please do so.

Use the work flow starting on this page. I have picked Thunderbird for you. https://support.mozilla.org/en-US/questions/new/thunderbird