Webmail works, but email won't send from Mac Mail

Richard Lewisohn1 wrote:

Thanks. The settings are correct (and I was on a Live Chat with the email support for 90 minutes this morning to verify that!).

re: Mail.app

For problem accounts the go to way to sort things out is to delete the account(s) from the Mail.app, then add it back.

Remove email accounts in Mail on Mac

Remove email accounts in Mail on Mac - Apple Support

Add email accounts in Mail on Mac - Apple Support

Add email accounts in Mail on Mac - Apple Support

Note—

IMAP accounts stay on the server, so no local loss, when you re-sync

POP accounts download and remove from the server—therefor save your inbox/sent box if you want them

“On My Mac" is just that, local folders you created and moved mail into. So no loss

Download and run Etrecheck. Be sure to give it Full Disk access before running.

Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Additional Text button to paste the report in your reply.

Then we can evaluate the report to see if we can determine the cause of the problem.

Who's your email provider?

Give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

.

You've installed some totally unnecessary and often system performance interfering apps:

 Antivirus software: Apple, Bitdefender, and Trusteer

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Also, unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, they aprovide false security from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Former Malware Distributor Kape Technologies Now Owns ExpressVPN, CyberGhost, Private Internet Access, Zenmate, and a Collection of VPN “Review” Websites. 

Uninstall Trusteer and BitDefencer according to the developer's instructions.

Richard Lewisohn1 wrote:

I had to change my email server, as the old one was being retired. When I first installed this on Mac Mail it worked. I had to revert to the old server to try and download more historic emails, and then deleted that and re-installed the new IMAP and SMTP settings.

Before going further I should add that I can send and receive fine with the new settings on webmail, my iPhone and also using the Spark mail app on my Mac.

I can receive email, but can't send it. When I click send I hear the 'whoosh' It then says 'sending message'. However it doesn't arrive, isn't in the 'sent' folder or in the 'outbox'. I feel it might be something to do with 'Internet account' settings not working correctly. I only come to this conclusion because Spark doesn't use Apple's 'internet account' settings.

If anyone has any thoughts, I'd be grateful. It's been driving me crazy!

Make changes to server settings...

Mail>Settings>Accounts>Sever Settings

Change Server Settings in Mail on Mac - Apple Support