"It is not possible to connect your call at this time" error

[dgmjr2018]

I am currently in Belgium because of my study abroad programme, and I've been having a lot of issues with receiving calls from the UK. Whenever I get a call from a landline or mobile, an automatic message - "It's not possible to connect your call. Please try again later" comes on my side, whilst the other person only hears the phone ringing. 

This is starting to annoy a little, as every time I get a call, I have to hang up and call back, and there are some withheld numbers that I cannot call back.  

[bristolian · Accepted solution]

Try manually selecting an alternate local network, see if the issue is consistent.

It may be a local network issue, in which case using another one can often resolve.