once i open an email , I cannot accesss another window in that email

Change the link-blocking setting that matches your Outlook version; in classic Outlook, enable links from the message’s InfoBar or check whether the message is displayed as plain text.

If you use new Outlook

1. Select the Settings gear in the upper-right corner.
2. Go to Mail → Junk email.
3. Under Security options, clear: Block attachments, pictures, and links from anyone not in my Safe senders and domains list
4. Select Save.
5. Close and reopen the affected message, then click its link.

Links are normally enabled by default in new Outlook, but that security option can disable them for senders outside your safe list.^1^

Only open the link if you recognize the sender and trust the destination.

If you use classic Outlook

1. Open the affected email.
2. Look for an InfoBar notification across the top of the message stating that links or external content are disabled.
3. Select the button in that bar to enable the content.
4. If there is no InfoBar, check whether the message is being displayed in Plain Text. Classic Outlook’s official troubleshooting specifically identifies plain-text messages and the InfoBar as the first checks for disabled links.^1^

If all messages are being forced into plain text, open:

File → Options → Trust Center → Trust Center Settings → Email Security

Then clear the option that reads standard mail in plain text, reopen the message, and test the link.^2^

If the link becomes clickable but no browser opens

This is a different condition from a visibly disabled link:

1. Open Windows Settings → Apps → Default apps.
2. Select your preferred browser again.
3. Verify that the browser handles HTTP, HTTPS, .htm, and .html.
4. Restart Outlook and test again.^3^

If the security option is unavailable or automatically turns back on, the computer may be managed by an employer or school. Contact that organization’s Microsoft 365 administrator and provide a screenshot of the disabled link and Outlook version, without including personal email content.

References

1. Links are disabled in Outlook for Windows email messages | Microsoft Support
2. I am unable to click on a link in my Outlook messages despite allowing popups in my settings. - Microsoft Q&A
3. Application not found - Microsoft Q&A