If you see one of following messages:
"Due to company policy, you can not request for absence in future"
"Your absence allowance is not enough"
it means that your absence year is not activated and entitlement not calculated yet.
Please follow the steps below:
Go to Configuration → Absence types → select the absence type and click 'edit' → go to the Requesting tab
From "Requesting is possible in" choose how long in advance employees can request time off and then "Save".
After changing the configuration, Calamari will automatically calculate new entitlement for the next year accordingly to accrual rules.
Remember that this configuration is related to one absence type. You should repeat above steps for each absence type if you want this setting to be applicable for all absence types.