Router causing email delays in Thunderbird?


Oct 9, 2002
I talked to someone on the phone 1 or 2 months ago. He and his wife each use Mozilla Thunderbird on their own computers. Around the same time, both computers started experiencing a strange delay when sending. After clicking Send, the pop-up would say "connecting to server" for several seconds. Then it would connect and send instantly. It would do this for all messages. New messages or replies. Even with no attachments. I don't recall exactly how, but we determined that an older version of Thunderbird didn't have the issue. I helped him configure Windows Live Mail with identical email account settings and messages would send instantly from that.

He continued to troubleshoot the Thunderbird issue on his own and called me back days later. He discovered that newer versions of Thunderbird have a compatibility problem with his router(?!?). I think it was a Netgear router. After replacing it, the problem was immediately resolved for both computers. Now, sent email messages in Thunderbird go out immediately.

Well, I thought that was just one peculiar case, but now I'm trying to help someone else experiencing the same exact issue. He has a Linksys WRT150N v1 running DD-WRT v24-sp2 (07/22/09) mini. Makes me wonder if the other guy with this issue was also running DD-WRT.

I don't know which replacement to recommend. I know that model is pretty long int he tooth, but this guy is *not* a computer guy and would have a heart attack at the suggestion of him replacing the router himself. Is there a setting I can suggest changing that might fix the issue without replacing the router?


Diamond Member
May 14, 2003
I can't imagine a bug from 2007 would still be an issue, either for DD-WRT or Thunderbird. I would look at the DD-WRT logs (viewing logs in browser might be easiest) and see if there is anything else causing the delay.


Diamond Member
Apr 20, 2013
Everybody I know using Thunderbird has odd issues such as this. My recommendation to people is to dump it for something that works properly. My parents have been complaining about a sending delay for a month or so now.