Incoming frontiernet.net mail not working on 4S

For some reason, my email address “****** has stopped receiving emails on my iPhone 4S, IOS 8.1.1, about a week ago, until then, there were no issues. I have two other accounts with frontier that are not a problem. All three accounts work properly on my MAC pro tower running Yosemite 10.10.1.

Has anybody run into this problem?

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