Workflow notifications by email just started to fail

[KevinSJC]

Hi!

I built this site a year ago on SharePoint Online, and it has been working great up to about a week or so ago. The workflow has 2 email notifications that fire upon submission of a new form. The first email notification does go out, I am BCC'd so I see them. The second email doesn't always go out. There are no errors recorded by the workflow, it just completes. Obviously something changed, but not on my end. 

• I tested the form with a test submission and both emails were received.
• I then had an end user submission shortly after, both emails came through.
• Then later, 3 other submissions came in, but ONLY the first email was received, the second did not.

I know the workflow is technically correct as it worked great for a whole year, and did so with my testing. I changed nothing over the last year. I have no clue what to look at where SharePoint is hosted on O365. 

Thoughts? I was hoping for some logging somewhere for email notifications, but I'm not finding anything.

Thanks, Kevin

[#2]

Could you let know are these workflows 2010/2013? How many instances of the workflows are in progress? We haven’t hear any issue on our tenant so far. Could we think for use flow as alternative or even recreating the workflow.

[#3]

@NiteshRanjan, it is a 2013 workflow with only one instance. It fires for new submissions and any modifications, made to complete every time. I am assuming the email is firing, but not getting to me for some reason, thus my reaching out looking for ideas on how to troubleshoot. 

Weird thing is, one that failed last night just worked this morning after I manually started the workflow.

Thanks, Kevin

[#4]

@KevinSJC I would consider @NiteshRanjan's suggestion to consider using Microsoft Flow. Flow does a pretty good job of letting you know why a step might have failed, and Flow is generally a better tool than SP Designer's workflow toolset.

[#5]

@Matt Coats 

Hi Matt!

I know nothing about Flow so this will be a learning curve for me I'm sure. I feel like I will duplicate my work and then end up with the same results as it seems like the POF is somewhere from the SharePoint farm at MS and our email server. The workflow is working sometimes and has been perfect over the last year, only recently has it dropped emails randomly. I was hoping for some logging that could be looked at to verify the email request was sent to the mail server and what was sent from the mail server for notifications. If the workflow itself was the issue, then I'd expect 100% of the time for failures.

Thanks, Kevin

[#6]

Agree here, classic workflows in SPO are not very trustable so if you can, move to Flow to avoid thise kind of problems. By the way, have you checked in the Workflow health dashboard that everything is fine? You can reach it from the status page of youyr workflow

[#7]

@KevinSJC, I see your point about mail logs. While I can't help you with that, I can tell you that you're facing a bit of a black box in the way that SP Designer kicks out emails vs. how Flow does it. With SP Designer workflows, you're leaning on a system account that you have little to no access to (I've not looked to see what logs are available for it). Flow requires that an O365 account send emails and does not use a system account--while this is inconvenient in that we don't have access to a system account anymore, it does give you complete visibility into that email account. So, problems would be less likely to occur in a black box.