Archos 50e Helium / Android Lillipop 5.1.1 Dialer issue. Unknown Application error.

[Trebz]

Hi All

I just bought an Archos 50e Helium Dual SIM with Android 5.1.1 installed.

I use my work SIM in slot 1 and my personal SIM in slot 2.

When I receive a voicemail notifier from SIM 1 or try to dial '1' from SIM 1 I get a pop up error message stating 'Unknown Application'.

I'm quite keen to resolve this issue but don't know where to start.

Can you offer any advice.

Thanks in advance.

Trebz