After 30 days of a failed payment [1] or 30 days without contacting JetBrains servers [2] it will only allow you to open their software briefly before "the product will gently notify the user and will allow some time to connect to the Internet before asking to close the application".

[1] https://sales.jetbrains.com/hc/en-gb/articles/204344871-Does...

[2] https://sales.jetbrains.com/hc/en-gb/articles/204348441-What...