"No input file specified."

When I use the ISBN lookup (https://www.librarything.com/isbn/), it will work for a few books, then stop working, taking me to https://www.librarything.com/verify.php, which only says, "No input file specified."

What's going on with this? Yes, I'm using this feature repeatedly.

A few questions that will help the staff:

What system are you using (PC, Mac, Linux, iOS device, Android phone)?
What OS version?
What browser and which version?

Also, what happens when you search for something other than ISBN? I tried searching by words, and it kept working as long as I was willing to throw stuff at it. Knowing that would let us know if it's the search in general or just ISBNs.

Also can you give a few examples of ones that failed?
And what sources you're using?

Also - are you using it manually or are you using some scripting? I wonder if you may be hitting some kind of a threshold based on number of request in a short time.

>4 AnnieMod: Tim made a reply in 2015 that there is a cap on hitting the the ISBN lookup URL https://www.librarything.com/isbn/

Reply is at: https://www.librarything.com/topic/188302#5069987

I just tried and got one positive return, using https://www.librarything.com/isbn/9780374280598 but then the next one and subsequent are redirecting me to the verify.php page.

>5 Nevov: That’s why I was asking - I know that there was a cap somewhere in there. :) I did not remember how low it may be.

Closing as not a bug, but limiting as mentioned at >5 Nevov:

3 is not enough. This is a serious difficulty. 3 in a minute? Fine. 3 in an hour??? (Edit: Testing shows ~30 minutes)

I'm going through 1000 books in Delicious Library. I'm still looking them up and using up LT resources; I'm just doing it by laboriously copy-pasting the ISBN into the Search field.

>8 Calion: So you aren't adding books by way of the https://www.librarything.com/addbooks webpage? You're searching for the books on Librarything?

>9 gilroy: No, I'm not adding books. I mean, I already have, by importing from Delicious Library, but no, I'm using LT to help me categorize my books in DL.