Hi ​@monikalyzwa - Thanks for raising this. We have a ticket open with our support team so they can start looking into this. In the meantime, you may find success by white listing our sending IP addresses at 167.89.22.99, 149.72.200.43, and 149.72.248.16 and making sure that notifications@calendly.com is on your safe senders list in your email service.

This doesn’t seem to be causing any widespread issues as of yet, so I suggest trying the above first, and letting me know if issues persist.

Hello David. I do have notifications@calendly.com on my safe senders list. I’ve contacted the hosting provider to ask abous IPs, but since these are publicly blacklisted, they cannot add them to black list - we must understand that logic. 

So the only way is for Calendly to take action and make sure your IP addresses don’t appear on public blacklist. Please resolve that issue as soon as possible, because lack of information about new and cancelled reservations is literally destroying my doctor’s office practice. 

Hi ​@monikalyzwa - I took some time and worked with our email service provider on this to dig into this a bit deeper. The issue you're experiencing is related to UCEPROTECT, a disreputable blocklist provider. UCEPROTECT is not considered a valid blocklist due to their shady tactics and frequent false positives. Many companies, have globally blocked their servers for this reason. Our email vendor, Sendgrid, recommends notifying your mailbox provider that this blocklist is impairing your ability to receive legitimate emails. You can find more details here: https://blog.sucuri.net/2021/02/uceprotect-when-rbls-go-bad.html.

If you’re still having issues with email deliverability, I’d recommend reaching out to our support team for some more details, as they could look into the specific errors of your Calendly emails.

Let me know if you have any other questions!