On Thursday, T-Mobile, Verizon, and AT&T customers lost signal. The company with the biggest issue was AT&T.
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Hours after service was disrupted, the cellphone provider said it connected all customers. We're still waiting to find out why they needed to be reconnected.
We know that on Thursday morning, tens of thousands across the country lost signal. It wasn't fully restored until this afternoon.
The National Oceanic and Atmospheric Administration said the sun did emit two strong solar flares last night and this morning, but based on the intensity of them, it's unlikely to have caused the outages.
Another explanation could be a cyber-attack. Experts said because an infrastructure went down, that's why an investigation will take place.
Another reason, experts said, could be someone hitting the wrong button.
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"The first usual suspect is us humans making a mistake, which we do," Syracuse University associate professor Lee McKnight explained. "Perhaps someone (Wednesday) night when refreshing the AT&T network software, as often happens, and daily happens, around the world for a different software, made an error."
In a later update, sources told ABC News that AT&T's outage was caused by a software update gone wrong. Sources say there was nothing malicious about the outage. AT&T has declined to comment on this new information.
Verizon and T-Mobile customers had issues, too. But the providers say it wasn't their fault.
They said it was most likely that customers who connected to another carrier to text and call at that time were impacted. They said their systems are fine.
Harris County Office of Emergency Management leaders said if you lost service, you should still be able to call for help.
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As for reaching others, experts said you could use Wi-Fi. If you have it, you can still make wireless calls and texts.
Experts said you can get something called an internet backpack. But those can cost thousands of dollars.
A cheaper option is having a landline.
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