many of them stop at the first question
That's not uncommon. People see the link, click there, read what's the questionnaire is about, and then close the browser tab.
I still had some questions blank even though 1) they are required 2) she has obviously sent in her answers.
As a first step, please check which questionnaire was used, see variable QUESTNNR. Then go into that questionnaire and check if he question is placed on any page of that questionnaire.
If that is the case, you may take a look at Collected Data -> View Data and use the print view to check if the repsective page has been shown in the interview. If you're using filters, the questionnaire may skip questions or pages. Depending on the filters.
It's also generally a good idea to take a look into View Data. Because the color shows you if the question has been answered (green), showed up but hat not been ansered (red) or if it did not show up in the interview at all (white).
In some cases, the collected data site also writes that "the respondent did not submit page 03."
Then the LASTPAGE variable should display the value 2. So, respondents closed the browser tab after submitting page 2.