For “Field can not be filtered in a query call” Exception in Salesforce, check the following:

1. Check whether it is Text(Encrypted) field since it cannot be used.

https://www.infallibletechie.com/2014/11/textencrypted-field-in-salesforce.html

Encrypted fields that use the probabilistic encryption scheme can’t be used with the following SOQL and SOSL clauses and functions:
Aggregate functions such as MAX(), MIN(), and COUNT_DISTINCT()
WHERE clause
GROUP BY clause
ORDER BY clause

2. You can’t filter by text area fields in SOQL.

 

3. Check whether field has Filter Property.

Example Exception: ‘Application’ can not be filtered in a query call