JPMorgan Chase said in a tweet Thursday that its website and mobile app were functioning normally again after being offline for the day, but it did not provide a reason for the outage.

"Our digital channels are back to full strength," the evening tweet said. "Thanks for your patience."

A 10:45 a.m. tweet from the bank noted that “some functions of http://chase.com and our Chase Mobile app are not working properly. We are working hard to fix the issue and are sorry for the inconvenience.”

That sole message did little to mollify customers, who vented on Twitter that in addition to online and mobile banking, they were discovering systems were down at some branches as well.

Some bank customers posted images on social media of error screens they were receiving while trying to access their accounts online.

A company spokeswoman said the issue was resolved and there wasn’t any kind of attack.

JPMorgan client screenshot of error page

This is the second instance in recent memory that JPMorgan online and mobile clients were affected by a service outage.

Last May, JPMorgan customers nationwide could not make online and mobile payments due to unspecified technology issues. Bill pay and Chase QuickPay were rendered offline for several hours. Some customers could not see their account information.

Customers venting about offline services on social media has become a recurring theme.

In the past month, Wells Fargo angered customers for a double-billing gaffe online that it said was caused by an “internal processing error.” Glitches at Capital One caused many customers to be charged multiple times for the same debit card transactions.

Last year, snafus with ATMs, debit cards, apps and online accounts befell several banks.

Suleman Din

Suleman Din

Suleman Din is technology editor of American Banker and Financial Planning. Follow him on Twitter at @sulemandn.