domains are blocked on my soi sms long code leads

I get about a thousand sms leads a day
I respond to each of them with a url

I have done this with twilio using long codes for local numbers for years..

now my domains get blocked all of the time, they seem to be blocked by the receiving phones service provider


even brand new domains I just set up get blocked quickly.

I have about 10 domains that I am using across a few dozen phone numbers.