If automatic subscription does not work, you can subscribe to a calendar manually.
On the Ημερολόγια page, select a calendar you like.
Click Επιλέγω.
If you are not logged in to WebCal.Guru, you will not be able to modify subscription settings and you will have significantly smaller selection of calendars. In this case, jump directly to Step 4.
Adjust the subscription settings if needed and click Προσθήκη στα ημερολόγιά μου.
You will be taken to Τα ημερολόγια μου page. On the calendar you just added, click next to Λήψη and select Αντιγραφή διεύθυνσης στο πρόχειρο.
On the home screen of the device, tap Settings.
Turn the device to portrait orientation, scroll down to Calendar and tap it.
Tap Accounts.
Tap Add Account.
Tap Other.
Tap Add Subscribed Calendar.
Tap the empty input field.
Tap Paste.
Tap Next.
Tap Save.
Updated 8 Feb 2023