@Seth Berg I see that you had used the "Enable" option available in VM's "Logs" section to enable Monitoring, as shown below:
This option installs the old "Log analytics agent" or (OMSagent). As seen in the screenshot above (for extesions), OMSAgentForLinux is stuck in Transitioning state which is why you are getting the error.
As the state of agent is Transitioning, it appears that the agent installation was kicked off, but it never finished/reported back its status to Azure/Log Analytics Workspace. In this regard, the troubleshooting steps mentioned in the following article should help resolve or diagnose this issue further - Troubleshoot issues with the Log Analytics agent for Linux
If you have already removed the agent from the VM manually, use the Remove-AzVMExtension
cmdlet to try remove the VM extension - if it errors out, the returned error message should give a better understanding of the issue. Please see the following for more details - Remove-AzVMExtension
Finally, you could also try purging and reinstalling the agent using the steps mentioned here - How to reinstall Operations Management Suite (OMS) Agent for Linux
Please let me know if you have any questions. Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.