Cannot Create InboxRule on one individual mailbox

Cannot Create InboxRule on one individual mailbox

This one user when trying to create a rule through outlook throws the
generic "One or more rules cannot be uploaded to Microsoft Exchange and
have been deactivated. This could be because some of the parameters are
not supported, or there is insufficient space to store all of your rules"
This user does not have any other rules set, i've adjusted the rule quota
to the max value.
When I try to create a rule using the powershell cmdlet New-InboxRule, I
get the following error (The command works for multiple other mailboxes on
the same database, as well for other users) :
There was an error saving the rules.
+ CategoryInfo : NotSpecified: (0:Int32) [New-InboxRule],
StoragePermanentException
+ FullyQualifiedErrorId :
569675E6,Microsoft.Exchange.Management.RecipientTasks.NewInboxRule