'Too many recipients' is normally associated with sending more than the normal sending allowance, typically 50 recipients per hour or 500 per day when sending whilst connected to the TalkTalk broadband network. So, if you trigger one of these limits you'll wait for an hour or from 1 to 24 hours if the daily send limit has been exceeded. Note that sending limits are much lower when sending from non-UK networks if the send location is declared as high risk for spam. And heads up that the recipient count is the number of email addresses sent to not the number of mail messages.
By now, you'll have realised that the purpose for these sending limits is to limit the adverse effect of spam being sent from the TalkTalk network.
But the 'Too many recipients' can also be triggered by the spam protection device of identifying too many 'wrong' recipients if the address is wrong or the mailbox does not exist or the recipient mailbox is rejecting the mail as spam.
The error message usually has a TT code so if you could let me know that code it would help identify the full reason.
Thank you so much for the swift response. There were actually 47 recipients, although obviously I had sent other emails during the day. I had not realised when I researched the limit that it included other emails sent individually within a 24 hour period. The TT code was 550.
A probable indicator that it was the hourly sending limit that got triggered. That would normally come up as 453 4.1.1 Too many recipients (TT501).
Thanks for taking time out to let us know. We always appreciate your feedback.
BTW What program did the troubleshooter say was incompatible?
The troubleshooter said "Thunderbird is incompatible" which makes no sense whatsoever to me since I have always used Thunderbird for that particular email address. I think it more likely that talktalk has a limit (spam?) on recipients because allegedly Thunderbird's limit is 60.
Another thing which puzzles me is that the Troubleshooter always says I have Windows 8 but as far as I am aware I bought this laptop new and equipped with Windows 10. Go figure ...
Thank heavens I don't require anything more complex from my system!