Signal has been adding so many new users that it experienced technical issues today.

Signal is a messaging app that is widely considered one of the most secure communication platforms in existence. While the app has been popular among privacy-conscious users for some time, it has received a major boost since WhatsApp announced it would start sharing user data with other Facebook-owned companies.

In fact, according to U.S. News & World Report, “Signal was downloaded by 17.8 million users over the past seven days, a 62-fold rise from the prior week, according to data from Sensor Tower. WhatsApp was downloaded by 10.6 million users during the same period, a 17% decline.”

That growth hasn’t come without issues, however. For much of the day today, Signal has been experiencing technical difficulties, which the company has said is a reflection of its growth.

The company later tweeted that it is making progress toward a resolution.

Signal’s growth is good news for privacy advocates, and signals (pun intended) a bright future for the messaging app.