Due to salesforce timeout and memory limits there's a limit to the maximum number of questions a user can have in single form.
We recommend a maximum of 300 questions. If you have single/multi-select questions with extremely long response options lists, this also impacts the maximum number of question you can have in a single form. We suggest that you break the form into multiple forms across multiple tasks to gather the same amount of data within a single Job.
Things to keep in mind in future:
Surveys with more than 200 questions but lots of options in Single/Multi Select Questions are also not supported. Please split into multiple surveys during design.
The TOTAL number of options across ALL Single-Select and Multi-Select Questions should not exceed 1000. (Eg. 100 questions with 10 options each.) Otherwise the form runs the risk of triggering a View State Limit Error upon using Scoring or Logic.
The maximum total number of options for a single question is 99.