my mail is not being delivered from yahoo.com

I get "connection to server pop.mail.yahoo.com timed out" every few minutes. mail is not usually delivered, and some mail that's delivered is from two-three weeks ago that I've already gotten. It seems that I've stopped receiving mail for account "redacted@frontier.com" after 10/8/26. Mail that's sent to other accounts seem to be delivered OK, but mail that's sent to this account doesn't show up. I've received at least some mail for account "redacted@frontier.com" for 10/9 and 10/10. Not sure if I'm getting everything. Mail seems to be received at the yahoo.com website for both email addresses [redacted@frontier.com and redacted@frontier.com]. At least I hope it is! Mail also seems to be received using the yahoo app for Android [phone] and yahoo app for iPad.