Biggest challenges in Project Management in IT

Hi everyone,

those you have read this blog probably know that I work as a developer in one of the telecommunications companies here in Stockholm. At the moment we are facing some challenges that I thought it would be interesting to share with you and hear your own experiences and hopefully even examples on how to overcome such challenges.
Some of the biggest challenges we face are as follows:

1. Unclear Goals.

The project I am working on at the moment is creation of the new app for the company that would in the future replace the existing one. However, from the very beginning the product owner hasn't been clear on what we should focus the most: creating and MVP? releasing the new product as soon as possible? focusing on building a beta?
Not having a clear goal or a clear vision within the team has slowed down the project significantly.

2. Inadequate Communication.

A success of every project is closely related to how well the team communicates within and outside the team with manages and stakeholders. In our case, historically, there has been lots of miscommunication within the team. On a daily basis, developers have to communicate their ideas to the product owner and BA (business analytics), as well as closely collaborate with designers and UX. The technical gap sometimes prevents reaching the common understanding.
Recently, we started working agile with scrum and the effectiveness of communication increased significantly. Hopefully, I will write about my experience with scrum in another blog post.

3. Unrealistic Deadlines.

Another challenge we are facing is unrealistic time planning. The estimations we do often are not accurate, and makes the whole team feel more stressed, which leads to the more erroring code, not well thought system architecture and not user centric designs.
Since we are starting working with scrum and agile, I am hoping that we will become good and iterating and most importantly learning fast on how long specific tasks take us.
As I mentioned in the beginning of this post I would be very interested to know what challenges you are facing on a day to day basis, and most importantly, how to you tackle those challenges?