The online services and website of one of the United States' biggest banks - Bank of America were inaccessible to users early on Friday. More than 12,000 reports had been made on DownDetector as of 11:15 AM (local time). 

The bank posted a message on its website saying it is looking into the problem. It reassured customers their accounts were secure.

“Some customers may be unable to access Online Banking at this time. Your accounts continue to be secure. We are actively working to make our site available again to all of our customers as soon as possible," Bank of America’s website said.

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"We're aware some clients are experiencing slowness as they try to access account information. We're working to improve the situation asap. Client information remains safe and secure," a BoA spokesperson told Insider.

Customers, on social media, complained that they cannot access their balances or transfer money. Many said that it was the first day of the month and they had bills and rent to pay. 

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"Lmfao Bank of America app not working on the 1st of the month when people have to pay bills???????" a Twitter user said. 

"I feel like the Bank of America app is holding my Friday hostage," another one tweeted. 

The bank has not made an  official statement about the cause of the outage yet. 

In September, Global Finance named Bank of America as the 'Best Digital Bank'. The bank is also ranked number one for online and mobile banking by JD Power.