Mail.app v. Airmail and other apps in a wi-fi network
I am in a hotel, no problem to connect to the local wi-fi network (I am writing this text here). Airmail, Safari and Roccat connect and work perfectly. Also AppStore and Software Update, it indeed worked OK earlier today with two updates.
Mail.app does not connect, though. There are 2 gmail accounts, and one icloud mail account. In order to read e-mails in these account, I must use the browser. Airmail is used for secondary e-mail addresses, and did not try to add my accounts.
This issue is not specified here:
Recommended settings for Wi-Fi routers and access points - Apple Support
Thanks