Error message, "www.google.com. PR_END_OF_FILE_ERROR".
When trying to navigate to websites I very frequently receive the error message, "www.google.com. PR_END_OF_FILE_ERROR". (1) This is an intermittent behavior happening on websites that were accessible previously and then become accessible again on later attempts, (2) It happens on websites that I have used satisfactorily for years. (3) It happens on ones for hospitals, banks, etc. which are known to be secure. This occurs after waiting for a period of time, like a timeout error would. I do let my copy of Firefox do its default auto updates.
Please advise how to end these errors so that I can reliably use Firefox again.