I'm skeptical of their claim, as I use the site at least once a month.

Are there particular parts of the site that cause problems, or can you not even navigate from the home page or do Zip code lookups?

Assuming it's not a problem with a missing plugin, could you try "the usual"? By which I mean:

If a site is generally known to work in Firefox, these are general suggestions to try when it stops working:

Cache and Cookies: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes. If you do not see the number going down on the page, you can reload it using Ctrl+r to check progress.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click (on Mac Ctrl+click) a blank area of the page and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"
• click the padlock or "i" icon in the address bar, then the ">" button, then More Information, and finally the "View Cookies" button

In the dialog that opens, the current site should be pre-filled in the search box at the top of the dialog so you can remove that site's cookies individually.

Then try reloading the page. Does that help?

Testing in Firefox's Safe Mode: In Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement? (More info: Diagnose Firefox issues using Troubleshoot Mode)

I asked my tech/tutor to translate the answer above and he said that was to clear out the cache. Since I do this once a month, he said having old cookies would not be the problem. He tried using Internet Explorer to access the usps.com pick up package page and the page was faded out. In other words, IE didn't work. I have written to usps.com again. Fortunately I live in a small enough town where I can contact a real person at the post office to pick up a package. Thank you for your detailed reply.

Hi EdithAnne, I guess if you have to describe my entire post in two words, clear cache is good, but there actually are three completely different things to try there. Sorry you didn't feel confident enough to try them yourself; I'll have to work on my writing style.

In Firefox cookies are not stored in the cache. But if you clear your cache using the "Clear Recent History" feature, you may also be clearing cookies at the same time. That dialog has a details panel that lets you select different kinds of data to clear.

If IE also doesn't load fully, or grays when you try to use the features, I wonder whether there is some common factor in the background that is blocking some access to the site?