LinkedIn does not allow you to run any more searches. You need a paid LinkedIn account. If you open your search using the globe icon, you can see what is happening.

You have a free LinkedIn (Free) account and can only use a few pages of LinkedIn search. After that, LinkedIn tells you that you need to upgrade.

You can check this yourself by opening your search and switching to page 10, for example.

With a Free account, you also need to follow the rules below.