Re: Newsletter subscription limits?
Many ISPs limit the number of emails sent over a short period of time as a spam-prevention tool. One ISP I use allows 300 when I send newsletters. Another allows 600. You might want to check if your ISP changed its limits recently
On 1.9.2 when you send a newsletter, you could get a blank page when it completes. This has been fixed in later versions (not sure which version) to give you the correct page. The newsletters were sent in this case. I am not sure under what conditions you would get a blank page, but I noticed it. I updated and this was fixed.