I too was having the same issue. Unfortunately I deleted my account and have not been able to re-enter it. I just found a "fix" on the Blackberry Knowledge Base, Article Number: 000048806 First Published: May 09, 2018 Last Modified: May 09, 2018. It is instructions for adding AOL to your BB, they are now instructing you to add it as a POP mail account, no instructions for IMAP for AOL. The link is below. I just tried it and it works fine now. However, it only syncs 90 days and does not give you access to all of the folders created under the Inbox unless you created them in your AOL mailbox. I use Outlook and I have an extensive amount of folders. Very frustrating but at least I can see my new emails and send. I don't understand, IMAP works fine for AOL everywhere else, on my iPad, iPhone, and Windows Laptop. Trying to stick to Blackberry but they are making it very difficult, I guess that is their goal :(
Unable to add AOL email account to a BlackBerry 10 smartphone