Intermittent freezing on Search

[danenglish2]

I have a .NET core console app that runs 24x7, checking mail every 60 seconds. After a week or two, it eventually freezes at the search call. The app is then completely halted until I close and restart it. The relevant code is below. Any suggestions?

using var client = new ImapClient(server, 993, login, password, AuthMethod.Login, true);
IEnumerable uids = client.Search(SearchCondition.Unseen()); // execution stops here intermittently