failed generate html.[err]The following has evaluated to null or missing:
==> xParam.filter.solution [in template “1727259361752985602” at line 97, column 6]

Tip: If the failing expression is known to be legally null/missing, either specify a default value with myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthessis: (myOptionVar.foo)!myDefault, (myOptionVar.foo)??

The failing instruction:
==> #if xParam.filter.solution != “” && x… [in template “1727259361752985602” at line 97, column 1]