Hi Ruma1991,
To be honest, the possibilities are numerous.
The most common case is the following, where the field is set to read-only.
Maybe it is because the security role does not have enough permissions to read but not modify.
Another possibility is that the field is checked as a read-only field in the designer.
It is also possible that a business rule has been triggered or that JS has set this field to read-only.
I suggest you check the connection form to rule out these possibilities one by one.
