Most often, a pop-up blocker in your browser is preventing your preview windows from opening. Pop-up blockers in most browsers offer a setting to "Accept pop-up windows from this site" or "Always allow pop-ups from this site." Read below to see how your browser handles pop-up blockers.

Google Chrome

1. In Chrome, go to a page where pop-ups are blocked.
2. Click the Pop-up blocked icon in the address bar.
   
3. Click the link for the pop-up window you want to see.
4. Select Always allow pop-ups from https://www.proposalaccess.com. Select Done.

Internet Explorer 11

1. In Internet Explorer select the Tools button, and then select Internet options.
2. On the Privacy tab, if the Turn on Pop-up Blocker check box is checked, select Settings.
3. Enter https://www.proposalaccess.com into Address of website to allow. Select Add.
4. Select Close, then OK.

Firefox

1. When blocking a pop-up, Firefox displays an information bar (if it hasn't been previously dismissed), as well as an icon in the address bar. When you click either the Options button in the info bar or the icon in the address bar, a menu is displayed. 

2. Choose Allow pop-ups for this site from the menu.

Safari (macOS)

Safari for macOS has no per-website control over blocking pop-up windows. Pop-ups are either blocked, or they are not.

To allow pop-ups:

1. From the Safari menu, choose Preferences... and click the Security tab.
2. Ensure the Block pop-up windows option is not checked. Uncheck this option to allow pop-ups.
3. To block pop-ups once again, check the Block pop-up windows checkbox.

Edge (Windows 10 only)

Microsoft Edge for Windows 10 has no per-website control over blocking pop-up windows. Pop-ups are either blocked, or they are not.

To allow pop-ups:

1. Click the ellipsis icon (...) in the upper right corner of your web browser, and then click Settings.
2. In the Advanced settings section, click View advanced settings.
3. In the Block pop-ups section, click the switch to Off. Pop-ups are now allowed.
4. To block pop-ups once again, click the switch to On.