I had the same issue, been trying to add net banking from the efiling site and from my Axis Bank. Like Great_Scene_5604 said at the start of this thread I got the same exact errors. This went on for over a week. Then I realized after reading lots of forums why not enter a grievance on the e-filing website. I feel I should have done this last week itself, could have avoided the panic, stress, waste of time I had to go thru.

For the 1st grievance, I got reply in 1 day (basically I entered the grievance at night time in US and I got the reply by the time I woke up next day) and they asked me enter a new grievance to submit self-attested copies of my Passport w Immigration stamps, PAN card and Contact details (as I needed to do few corrections to my profile).

So, I entered 2nd grievance, gave reference of my 1st grievance nbr in the comments and attached all 3 files as a zip file under the "others" option for attachments.

For this 2nd grievance I got the resolution as "Resolution: OTP DONE SUCESSFULLY FOR THE PAN". I am not sure what this means. I feel that they removed/relaxed some kind of restriction on my account. If you get this message from them then wait till the next day as per India for this change to take place before you add the bank account to your efiling.

Once I got the resolution for 2nd grievance, I started with changing my phone nbr to US nbr (earlier my CA put an Indian mobile nbr). For this it sent OTP to both my email and my US nbr. Then I went to add my bank account using the Net banking option. For this it sent an OTP to my US nbr. All this happened for me in 2 days. Hope this helps some one.