Here's a list of IPs for our emails if your provider wants to double check the availability:
Alternatively, users can end up on our bounce list if they have blocked the emails themselves.
firstname.lastname@example.org was not found on our email return list, so should be receiving emails from our system currently.
I also see several cases here referring to other users at your company with the same problem. For this reason, I am going to suggest you contact your Email or Network admin to ensure that the IPs 18.104.22.168, 22.214.171.124, 126.96.36.199, 188.8.131.52, 184.108.40.206, and 220.127.116.11 - 18.104.22.168 are also white-listed.
My email address email@example.com is not receiving an email invite from your user manager panel, it shows up green as successful, but nothing appears in my firstname.lastname@example.org outlook web inbox. I have resent it 3 times, checked spam /junk, checked our exchange email quarantine, nothing.
I have tried sending the invite using a different browser as well.
The inbox can send and receive other emails successfully.
The account is showing up as activated, I have assigned it a temporary password of password1 which you can use now to sign in with. I will check our email bounce list and make sure your email address is not on it.