When using the Automatic Posting feature with the Mews integration you may notice that some charges do not get posted. You are able to see a list of these automatically posted charges and any associated errors from your Settings:
Go to Settings
Click on Integrations
Click on PMS
At the bottom of the page, see the Posting Charges Logs
An error that you may see is "Primary Contact must be synced with Mews.
This error means that the Primary Contact on the Booking where the charges are coming from is not synced with Mews and there is no Paymaster account. You will need to sync the Primary Contact with Mews or add a Paymaster to proceed with posting the charges.