Thunderbird email
For many years, I've used Thunderbird (now 78.11.0) to email just under 400 clients every weekday morning. Starting June 1, 2021, it refused to send unless I sent to under 100 addresses at a time. How do I get back to sending one email to the 400? I'm not spamming. My clients pay me for my information.
Wšykne wótegrona (3)
Who is the mail provider? They set the limit on sending, and maybe it was reduced to 100, which is a common limit. I presume you're trying to send to 400 in a mailing list, not 400 separate contacts.
I've been with Earthlink since 1992. They swear it's not because of anything they're doing. The error message is not from them, so Thunderbird seems to be the only other possibility, and it updated last weekend.
Earthlink says the limit is 500 for desktop apps or 100 with webmail:
https://help.earthlink.net/portal/en/kb/articles/earthlink-email-faq-update
so I don't know why you get an error. What is the exact error message? A screenshot would be helpful. The limits in TB are explained here.
You will find several recent posts on this forum about sending through Earthlink, which might be related to your issue.