Can't save new imported vocabulary

I recently imported a list of German words I had picked out while reading a paperback book. I’ve been working my way through them during the last week, adding the English translations and, where possible, examples from the Lingq library.

Since Friday, though, I have been unable to do any more. I can still open up the German word to edit it and add in a translation and example but when I click on “Save”, the window still stays on screen and it won’t let me save my changes.

Is there a limit on how many words you can import in a specific time period? Or is this a technical problem with the import function?

There isn’t a limit, so it seems like a technical problem. Is this happening only with newly imported words? Is by chance the phrase field blank when trying to save the LingQ? I wonder if adding a phrase would help - not that this is mandatory, but this is potentially one reason behind this.