Unable to void preauthorization in Mews POS

The reason for why you are unable to void a pre-authorization in Mews POS is sometimes the time duration since the pre-authorization. Card acquirer bank does not allow pre-authorization to be voided if more than 48 hours passed since you made or topped it. 

To solve this issue: Execute a small top-up, such as  £1 and then void the pre-authorization.