This is likely appearing too late to help many people. I'm sorry.
Right or wrong I waited until today (1/27) to buy my first tranche (the $10,000 e-tranche) of I bonds. I had it in mind to take advantage of their new and widely hailed "add a new funding source online" feature.
WHAT WAS I THINKING!
The add a new funding source online feature did not work for me. Checked Boggleheads. Others are experiencing this same TreasuryDirect failure. Very fortunately my original source of funds remains available to me and I was able to place my I bond order timely. But the funding will not be as I had planned and anticipated.
Were I smarter I would have sought to add the new funding source days or weeks ago. Maybe it would have worked back then. I dunno. It did not work for me today.
So don't log into TreasuryDirect assuming, as I did, their widely heralded and praised add a new funding source online feature is gonna work. It might. But then again it might not.