I was writing a new blog post about Microsoft Teams Panels, and guess what, dear reader? One user came across a new issue!! And he told me about it, so, let's talk about how to fix "Couldn't Connect to Workplace Join. Try again, or contact your admin".
Alright, first thing first, you may face this issue on Microsoft Teams Android-based system, and I've been hearing that many companies tell customers to try changing provider on their Android-based devices or restarting them, but that won't work, I mean, those options may work, but the main problem will still be there.
Note: We must delete the devices both in Intune as well as Azure AD, but when you delete devices via either Intune/Endpoint Manager or, Azure, you delete them on the other site at the same time. So, just make sure that they aren't around there on both sites.
You can check out Azure's step-by-step guide, or scroll down to check Intune/Endpoint Manager's guide on this blog post.
EDITED: Please follow this guide. However, in case it don't fix the issue, go to this blog post (Device Administrator Enrollment Requiered for Teams Android). That one has been so helpful for users that have face "Couldn't Connect to Workplace Join. Try again, or contact your admin" issue and any other ones. Also, please check yout DNS Servers and set it up manually, if needed. For instance, one service provider asked me for help one week ago because their costumer had been facing this issue, but the accounts were created at that moment, so... Long story short, I used Google Public DNS, and it worked. In other words, These 3 methods have helped me fix this issue in different situations and environments. 👌
Azure
Method 1: List of Devices
Go to portal.azure.com.
Under manage, Devices will be displayed, click on it, and then All Devices.
Now, I recommend you go over registered and activity dates since you need to delete the device on Azure. So, Microsoft generates new device ID for existing devices sometimes, why? Your devices was running Android 8, and now it's running Android 10, so it may have a new ID, for instance.
For testing purposes, I added users and then signed into different devices using those accounts, and then I deleted them in order to add new accounts, that's why you can find None as owner on my list of all devices. So, I can delete those devices used by no one. However, you could review and go over your list of devices and delete only ones that haven't been connected for last XX days.
As this is my tenant for testing purposes, I will delete all of my devices, but you must go over registered and activity dates to know what devices you should delete or, go to 2nd method: List of users, or Intune guide by scrolling down here.
Method 2: List of Users
On azure and under Manage, click on Users.
Look for the account that is facing this issue, and click on it.
Click on Devices.
Review and go over the list of their devices, check the box and delete some of them or, all of them, and click on OK button.