Landline dialled not recognised

[SWatts74]

Since yesterday a number that i call daily is now "not recognised" when I dial from my landline, however i can get through to the same number on my mobile, line. The number not recognised is with Sky also, and can call me ok. Any ideas what the issue could be?

[Highlinder]

@SWatts74  Have you tried dialing other numbers? Do they go through or does the same thing happen?

[SWatts74]

Hi, I have tried other numbers and they seem to work.

Gave Sky a call in the end and they believe the issue is a switch at the exchange.