Can't send emails. No changes made on my end. Again.....

I can no longer send email from any device...windows or android devices. I use Thunderbird on Windows and BlueMail on Android. I've made no changes to my accounts.

I have verified my email settings are up to date and correct. I can get mail on any device but cannot send. This has been going on for the last two days..perhaps longer.

Are there any known issues going on with the SNMP server?

Last time this happened (5 months ago) the problem was magically resolved.