The unexpected error occurs in PSWS call because of corrupted/conflicting cached contents, conflicting user data, incompatible web browser or ISPs network restrictions. PSWS is a component and a part of Office 365 services.

It is worth mentioning that phishing and malware messages are sent to quarantine directly in Office 365 by default. An admin user can view and manage these quarantine messages in the Security & Compliance Center.
What causes The Unexpected Error Occurs in PSWS Call?
- Corrupted/Conflicting Cached Contents: The web browser’s corrupted or conflicting cache can be the root cause of issues in the operation of many online-based services. Office 365, an online service, can also be the victim of this corrupted/conflicting cache.
- Conflicting User Data: Web browsers store different types of user data like login credentials and cookies. If this saved data is corrupt or has a conflict with the Office 365 admin portal, then you may encounter the PSWS error.
- Incompatible Browser: Office 365 sometimes shows incompatible behaviour towards different web browsers especially Chrome. If you are using a browser that is not compatible with the Office 365 Admin panel then you may face the current issue.
- ISPs Network Restrictions: ISPs restrict different network services and features to keep things safe and under control. Sometimes these restrictions block some legitimate service and feature required by Office 365 admin panel which will then result in the current problem.
Make sure that the problematic user has global admin permissions in Office 365 to view and manage the quarantined messages.

How to Fix the Unexpected Error Occurs in PSWS Call?
1. Clear the Cache of the Browser
Your web browser saves pieces pages and stores them on your computer’s hard drive, known as the browser cache. The cache of a website does not change from visit to visit of the user. If the cache has corrupt data or has conflicting contents with the website, then it can force the ‘unexpected error in PSWS call’. In that case, clearing the browser’s cache may solve the problem. We will use Google Chrome for illustration purposes, you may use instructions specific to your web browser.
- Launch Chrome and click on Hamburger Menu (3 dots near the top right).
- Now click on More Tools and then click on Clear browsing data.

- At the top, choose a time range as per your easiness. To delete everything, select All time.
- Now select Cookies and other site data and Cached images and files check the boxes.

- Click Clear data. Then restart Chrome and check if you can view, quarantine or delete quarantined messages and files in Office 365.
2. Use the Browser In-Private/Incognito Mode
The unexpected error in PSWS call can occur due to issues with the old user data, login credentials or cookies stored on the system. Most modern browsers have built-in functionality like incognito mode or in-private browsing tin which the browser operates without using any of this data. So, accessing Office 365 admin panel in the browser’s in-private/incognito mode may solve the problem.
- Open your browser In-Private Browsing/Incognito Mode.
- Go to the Office 365 admin panel.
Now check if you can view, quarantine or delete quarantined messages and files in Office 365.
3. Use A Different Browser
The error message which you are facing can also be a browser-specific issue. Google Chrome is known to have issues with Office 365 Admin panel’s quarantined messages. So, using another browser to access Office 365 Admin panel’s quarantined messages may solve the problem. For this purpose, the use of Internet Explorer or Microsoft Edge is recommended.
- Open the other browser (Preferably Internet Explorer or Microsoft Edge).
- Access the Office 365 Admin panel.
Now check if you can view, quarantine or delete quarantined messages and files in Office 365.
4. Switch to Another Network
ISPs use different protocols & technologies to limit the control of certain network services and features as part of their security protocol. This can cause an unexpected error in PSWS call. It will be a good idea to temporarily switch to another network to check if your ISP is not the cause of this problem.
- Connect to another network. You can use your mobile hotspot. You may use a VPN (use of VPN with Office 365 is not recommended).

- Now open Office 365 Admin Portal to check if you can view, quarantine or delete quarantined messages and files in Office 365.
Hopefully, now you can view and manage quarantined messages in Office 365. If you are still having issues with it then create a new in cloud local user with the Global admin role and use that user to view and manage quarantined messages