Video conferencing service Zoom is down after its users said they were experiencing audio and video issues.
The problem has been ongoing since 9am and is mainly affecting people in the UK, according to website DownDetector.
The Silicon Valley-based tech company has not yet acknowledged the problem which has been widely discussed online.
Social media users described being unable join meetings and said they were having audio issues during calls. Log-in issues were also being reported.
As of 4pm on Sunday, around 1,400 unresolved problems were being reported with the service.
The video conferencing software has rapidly grown in popularity during the coronavirus pandemic as millions turn to its group video calling features in order to work and study from home.
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The company said last month it has about 300 million daily meeting participants, up from 10 million in December.
The platform has come under scrutiny over a number of security issues, including the practice known as 'Zoombombing' where strangers break into group chats and show other participants explicit material.
Concerns over using video app Zoom are "normal speed bumps" in the rise of a new service, an executive at the firm has said.
Earlier this month, a church claimed a hacker broke into its virtual Bible study and streamed porn during the class.
Smutty content was played during a Zoom call hosted by Saint Paulus Lutheran Church in San Fransisco on May 6.
Elderly parishioners were forced to watch the x-rated video, leaving them "traumatised and helpless,” a lawsuit brought on behalf of the church reads.
St Paulus' is now suing video streaming service Zoom for not providing the adequate protection to keep the hacker out.
