Restarting the server is never a good solution.

If the job gets stuck, you have to find what it is doing at the time of blocking.

If it is a simple T-SQL job step, you can monitor the execution of the statements with the activity monitor or with the excellent stored procedure sp_WhoIsActive.

It could be blocking, or a query that got a suboptimal execution plan due to parameter sniffing or stale statistics.

Try to investigate it further and come back when you have more info.