A "malformed certificate" message suggests that the problem could be on Engrade's end -- meaning that Engrade.com either was issued an invalid certificate last week, or that their certificate has been compromised, and in either case it needs to be replaced.
As mentioned above, one of my browsers also notifies me of the same error, (but it is a very out-of-date browser). So, you are not the only person experiencing the situation.
Since (I am guessing that) you have an Engrade.com account/login, you might consider contacting Engrade's customer service department directly, and notifying them of the invalid certificate error, so they can investigate it, and help you connect successfully.
I checked their site for a customer-support contact. They only have an online-form, and don't list a phone number or email address. You might need to use another computer to visit their site to complete the form. The link to the Contact Form is:
Engrade.com: Contact
If you can successfully log-in from another computer, you might find a better "report a problem" link or additional customer-service contact information after logging in to your account.
Hope this helps,
P.S.: From experience, I should also let you know, that you should not be surprised if customer-service at any corporation you ask for help (whether it is Engrade or a local computer technician), is going to ask you whether you have proper security software on your computer, whether that software has been currently updated, and whether all Windows Updates have been done, and whether your computer is proven to be virus-free. If all of these are not done, some customer service departments will limit their support because they cannot prove that the problem really is not on your end, and they simply won't waste time "chasing a ghost" on their end. Being able to confirm that, within reason, you have isolated/prevented the potential issues on your end, will help you convince them that the problem is on their end.