limit on numbeer of reciipients?

There are no such limit on number of recipient however for large user base, you might get timeout issue. Please try to increase your PHP max execution time and see if that helps.

thank you for the prompt reply and suggestion. I set the execution time to 500 and reran but had the same problem. Execution just stops after 2 minutes, about 13% completed. I did find a warning the the error log file:

[Tue Apr 12 12:35:47.050754 2022] [fcgid:warn] [pid 52821:tid 139793755358976] [client 8.45.147.20:40363] mod_fcgid: read data timeout in 120 seconds, referer: https://www.wcfw.org/wp-admin/admin.php?page=send-users-email-roles
[Tue Apr 12 12:35:47.050786 2022] [core:error] [pid 52821:tid 139793755358976] [client 8.45.147.20:40363] End of script output before headers: admin-ajax.php, referer: https://www.wcfw.org/wp-admin/admin.php?page=send-users-email-roles

Also I did run phpinfo(); from the wordpress console to verify that the parameter was set to 500
Any thoughts on this parameter?

I did a test and the issue is most probably related to the max execution time. How many users are you trying to send emails to? Also, are you using cpanel or other hosting infrastructure. Thanks.

Thanks, I’m using DreamHost and they have their own version of cpanel. I just switched from using fast cgi to std 7.4 cgi and it now times out with no errors after 10 mins. So I’ve gone from 13% completion in 2 mins to 67% completion in 10 mins so progress is being made. I’m trying to send out about 1400 emails.
Maximum execution time make sense, any guess on what module apache, cgi ??

This basically comes down to PHP max execution time in your hosting environment. You need to set max execution time to about 20 minutes in your case as script processed about 60% in 10 minutes. I am afraid this is the only option for now. If you are not sure how to increase the execution time I found this article on Dreamhost that might help.

Thanks that was an excellent article. After some more testing, with the php timeout set to 1800, I consistently get a failure after 10 mins (600) of running with no errors in the error log file.
I’m thinking that there may be some limit it either apache or wordpress that is set to 10 min. but what?

I don’t think WordPress sets such limit. I think its your hosting that has set some hard limit on max execution time. Please contact hosting support to increase the execution time.