One of your filters uses a custom header that contains an invalid character, such as ':', a non-printable character, a non-ascii character, or an eight-bit ascii character. Please edit the msgFilterRules.dat file, which contains your filters, to remove invalid characters from your custom headers.
Úsáideann ceann de do chuid scagairí ceanntásc ina bhfuil carachtar neamhbhailí, m.sh. ":", carachtar dophriontáilte, carachtar nach ASCII é, nó carachtar ASCII ocht ngiotán. Cuir an comhad msgFilterRules.dat, ina bhfuil do chuid scagairí, in eagar ionas nach n-úsáidfear carachtair neamhbhailí i do chuid cheanntásca saincheaptha.