A lot of services reject numbers from known VoIP providers as a way to reject fraud (and I guess prevent people from defeating number-based marketing/advertising tracking by using unique numbers?).
You can work around that by using lesser-known providers. In the UK, Andrews & Arnold (https://www.aa.net.uk) provide UK mobile numbers which don't seem to be rejected by anything.
It’s about making bans for fraud and abuse more expensive to repeatedly evade. The expected value of a few extra spam messages is lower than the cost of a new number.
You can work around that by using lesser-known providers. In the UK, Andrews & Arnold (https://www.aa.net.uk) provide UK mobile numbers which don't seem to be rejected by anything.