‘No Mail Service’ is default, but without SparkPost set it will not send emails.
Will you share a screenshot of your SparkPost setup settings so I can review what it says? There may be clues here.
To find your SparkPost settings area head into wp-admin->Inbound Pro->Settings and scroll down to find the Mailer setup area. Alternatively you could search ‘Sparkpost’ in the settings search at the very top of the page.
Hi I notice one issue here and it’s a message returned by WordPress when we tried to create webhooks. It says UNABLE_TO_VERIFY_LEAF_SIGNATURE, which means there is something going wrong when we try to POST data to SparkPost API. This error doesn’t seem to happen when we connect to the SparkPost API using GET instead of POST. In order to send emails and interact with SparkPost we need to be able to perform both GET and POST protocol, though.
This is the first time I have seen this error message, and I think it may be what’s affecting sends.
The documentation pages above seem to suggest it has something to do with your SSL certifications, and possibly NodeJS, which is not typically involved in a WordPress instance so it’s a little confusing.
Because this issue seems to be server related I would send an support email to your host referencing this thread, and the error messages, letting them know that your external POST calls are having an issue and maybe they can shine a light for us.