I'm trying to change the SMTP server my router is using to send mail and it's not playing fair

I have TWO possible SMTP servers I can use. One office365 and one zoho

Whichever one I use, I do not get a test eMail neither do I get an error message from the router why message sending failed - even when I use a blatantly incorrect SMTP password

Is there some problem with the mail send facility or am I missing something really REALLY obvious??

Thanks

Edit: I also tried with my Yahoo mail account - still no joy

I have a local Mail Server - there is no sign of any attempted mail delivery there - using Port 25 or 487

Using Netcat on a PC, set to listen to port 25 reveals no attempt there either.

I do remember using it, in the dim and distant past, but it now seems totally dead

However, selecting "use SSL" does send something to Port 465. I don't have my Mail Server set up to handle that, so I don't know if it's actually doing something useful, or not.

It's erratic, to say the least ... it turns out that one of the test messages was sent - the other dozen weren't

I'm using port 465 with SSL enabled to sent to a webhosting ISP (krystal), and mine flow through fine (2925)

Sorry for the delayed response - i didn't get any notification that anyone had replied to my posts (and I AM subscribed for updates!!)

Mine also seems totally dead, whatever I try i get neither a test eMail sent, nor an error message even when I use blatantly incorrect credentials

Ah well

Maybe it's just broken

Simple checks:

use an IP address instead of a server name
Try a short simple username
Try with a short, non-complex password (obviously just as a POC)