The most common challenges that we can state are,

1: Technological advancement challenge. 

2: Rising competition/ rivals. 

As the world is getting tech oriented almost every work work depends on technology. But there are people who are not that much found of these kind of technology so it becomes impossible for them to catch with the flow. Also the updates are expensive so many companies are unable to afford them, as a result it is becoming tough to handle and recruit good employees. Not only this, even the population is rising and also the competitions. Recruiting eligible staff and handling them is becoming tough for these external effects. 

There are many other reasons too like, 

1: Global pandemic,

2: Traffic,

3: Local acceptance,

4: Political factors,

and so on.