QuickBooks Online's bank feed connections are a great asset to many businesses, and it's nice to see that you've been taking advantage of this feature. I appreciate the detail about when the feed stopped bringing in transactions for you, and I'm here to help you get back on track.
QuickBooks Online communicates with your banking website to pull in the transaction data to your books. Since that connection relies on the exchange of information over the Internet, the feed can sometimes go down because of a variety of errors. To help with figuring out why, the QuickBooks feed often includes an error message with a number code, which you can then research in-product through the (?)Help menu or right here in Community. For instance, if you've got an error code ending in (103), you can search something like "bank error 103" to find the related article. In that case, it's this one: Fix bank error 103
I encourage you to start with searching for that kind of article. If you can't find an article or the steps outlined don't resolve the issue, the next best thing to do is troubleshoot for cache and Internet issues. I've got a series of steps you can try here to see if these get the feed back in working order.
Reset your Internet or try on another computer or device
Try those out. For help with tackling this issue beyond that, the QuickBooks Online support team can help. With a number of back-end tools, the team member can not only review your connection to that bank, but also QuickBooks Online's connection to it. This is how you can get in touch.
Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat. Support is available from Monday to Friday between 9 a.m. and 8 p.m. ET.