EWS Enabled - Calendar Not Available

Occasional Visitor

EWS Enabled - Calendar Not Available

Our environment: SfB On Prem, Exchange Hybrid with Okta for MFA


Our issue: Our Trio 8800 systems are encountering an error where they are getting EWS deployed and can connect to SfB for calls and meetings but the calendaring service is showing up as "Not Available" and thus preventing them from being able to one touch into meetings from the device.


Phone Software Version:

Phone Model: Trio 8800

Serial: 64167F4EC022


On rooms currently logged in there is no issue but if a room goes offline for maintenance or the Polycom is disconnected for some reason it can't reconnect to the calendaring service.


Polycom Employee & Community Manager

Re: EWS Enabled - Calendar Not Available

Hello @JGibbs19 


Welcome to the Poly community.


Our records show that the unit 64167F4EC022 was sold by SCANSOURCE INC via CDW Logistics, Inc. back in 01/08/2018


Our Skype for Business FAQ has this post here:


Jan 17, 2017 Question: How can I troubleshoot simple Skype for Business, Office365 or Teams issues?

Resolution: Have a look => here <=


The above can be used to try and self diagnose the issue or post logs for other members to try and troubleshoot this for you.


If this fails please go ahead and open a support ticket.


In order to raise a support ticket, you need to work with your Poly reseller as they may need to do this for you.

End Customers are usually unable to open a ticket directly with Poly support. Available End User Poly services offerings are detailed here

If this is some sort of an Internet discounter providing your MAC address or your Poly devices serial will enable us to look up who would be able to support you. This may not be who you purchased the Poly device from.

If the unit is no longer within the warranty please be prepared to Pay Per Incident / PPI. This is all outlined in detail here

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier


If official support is required please check how to phone or open a case here

The title Poly Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.


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Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge.
Please also ensure you always check the VoIP , Video Endpoint , Microsoft Voice , PSTN or other FAQ's in the different sections
Message 2 of 4
Valued Contributor

Re: EWS Enabled - Calendar Not Available

Is MFA enabled in SfB as well? If not, you will need to disable MFA on the resource accounts the devices are using to sign in. The sign-in method used for SfB and Exchange must match. 

Message 3 of 4
Occasional Advisor

Re: EWS Enabled - Calendar Not Available

Same issue here, did you ever get this fixed?

Message 4 of 4