When Device Sync Does Not Work
The wrong address form, a mistyped password, or a phone quietly pausing the app.
Three causes cover nearly everything.
The wrong form of the server address. iPhone and Mac want the bare name; Android and Thunderbird want the full link. The setup screen shows both, labelled for the device.
A mistyped app password. These are long and are shown once. Paste rather than type.
Android pausing the sync app. Sync works for days and then stops, which looks like a connection problem and is a battery setting.
Known Issues
The device refuses the login
Usually the server address in the wrong form for that device, or the app password mistyped.
Check which address you used. iPhone and Mac need Server (iOS / macOS) — a bare name with no https:// and no trailing slash. Android and Thunderbird need Base URL — the full link with both.
If the address is right, generate a fresh app password and paste it. An app password is shown once and cannot be read back, so if you are unsure whether it was copied correctly, replacing it is faster than checking.
The account connects but no calendars appear
On Android, either no calendars were selected after the account was created, or the calendar permission was never granted. On any device it can also mean the account was added without calendars enabled.
On Android, open the account in the sync app and tick the calendars you want — nothing syncs until at least one is selected. Then confirm the app has calendar permission.
On iPhone, check Calendars was left switched on when the account was saved.
Sync worked for a few days and then stopped
Android power saving. The system pauses background apps it decides are idle, which stops sync without any error.
Allow the sync app to run in the background again and turn regular sync intervals back on. This can recur after a system update, so it is worth checking first whenever Android sync goes quiet.
Nothing in Zyntro needs changing.
I cannot find my app password
App passwords are shown once when generated and cannot be read back.
Delete that entry and generate a new one, then set the device up with it. There is no cost to doing this and no way to recover the old one.
A phone was lost or stolen
That device still holds a working app password.
Revoke that device's app password immediately. It stops syncing at once and no other device is affected — which is the reason for one password per device.
The events already downloaded remain on the device until it is wiped, so for a lost phone, use your phone provider's remote wipe as well.
An event I deleted on my phone came back
Either the deletion had not reached Zyntro before the next sync wrote the event back, or the meeting is not yours to delete.
If it is your own event, delete it again once the device shows it is in sync, or delete it in Zyntro, which is the authoritative side.
If it is a meeting someone else organised and invited you to, deleting it on your phone cannot work — it would remove the meeting for the organiser and every other guest. Decline it instead. The organiser is told you are not coming and the meeting stays on their calendar.
A repeating event looks wrong on the device
Repeating patterns travel as patterns, and calendar apps do not all render unusual ones identically.
Check the series in Zyntro to confirm the rule is what you intended. Remember that editing a repeating event changes the whole series — on either side.
I set up sync and my booking page still offers times I am busy
The commitments are not on a calendar Zyntro can see, or sync has not run since you added them.
Confirm the appointments appear in Zyntro after a sync. If they were added in a different calendar account on the phone — a personal Google account, say — sync does not cover them, and you want the inbound connection for that calendar instead.
Should I use device sync or the Google and Outlook connections?
They overlap, and doing both can produce duplicates on your device.
Device sync alone covers both directions and is usually enough. Use the Google or Outlook connections when you want Zyntro to read a calendar you do not sync to a device, or when you want Zyntro events visible to someone in their own calendar app.
My device will not save a change to a meeting
The meeting was organised by someone else. Only its organiser can change its time, title or location.
Check who hosts the meeting on its page in Zyntro. If it is not you, the change has to come from them — ask them to move it, or decline and suggest another time.
You can still answer it from your device. Accepting or declining is yours to do and is recorded in Zyntro.
I accepted a meeting on my phone but Zyntro still shows no answer
The answer travels on the next sync, so it is not instant — or sync is paused.
Give it a sync cycle and look again at the meeting's Attendees panel. If it still shows Awaiting reply, confirm sync is running rather than paused and that the account on the device has not been signed out.
Troubleshooting Guide
Does the device refuse to log in at all?
Did calendars appear at first and then stop updating?
Did calendars never appear at all?
Frequently Asked Questions
It would work, but it defeats the purpose. One per device means losing one device never disturbs the others.
No. It stops the device receiving changes; what is already there remains until the account is deleted on the device.
On the device's sync schedule rather than instantly. On Android that is the regular sync interval, which is why keeping the app allowed to run in the background matters.
No. That is the point of an app password — your real password never goes onto a device.
Yes. The device asks which calendars you want, and you can change the selection later.
