I have this piece of code here below:

$fq.=" + (fritidsboende_uth_from:[$fritids_uth_from TO *] 
AND fritidsboende_uth_to:[* TO $fritids_uth_to]) 
OR (fritidsboende_uth_from:'1972-01-01T01:01:00Z' 
AND fritidsboende_uth_to:'2019-01-01T01:01:00Z')";

I have noticed my app doesn't get anything behind the colon, in this part of the code:

  OR (fritidsboende_uth_from:'1972-01-01T01:01:00Z' // Notice the colon in the date string

I get this error msg: Unrecognized date string: '1972-01-01T01'. Nothing from behind the colon is there though.

How should I 'escape' it so that the colon is properly recognized?

Its PHP...

Thanks