This could be due to one or both if the following:
Control Panel > Features > Search: Minimum Searchable Word Length
Confirm that the setting is the smallest word size you are willing to let your users search for when using the "UBB.threads internal" search engine.AND/OR
, if using the "MySQL Full-Text" search engine:
Your database server could have recently been updated or had its defaults set.
Check this page in the documentation -- basically you set ft_min_word_len=3, restart the server, and rebuild your FULLTEXT indexes.https://dev.mysql.com/doc/refman/8.0/en/fulltext-fine-tuning.html
• You can use this query in Control Panel > Database Tools > SQL Command or the MySQL prompt to show the state of ft_min_word_len: "SHOW VARIABLES LIKE 'ft_min_word_len';"
• ft_min_word_len deafults to a value of '4' and is not by default listed in "my.cnf". To change it's default value, add: "ft_min_word_len = 3" to my.cnf under the [mysqld] section. my.conf is most likely located in /etc/, then restart MySQL or MariaDB. You don't need to restart the server.
• After changing the value of ft_min_word_len, any indexes you have must be rebuilt. To do the re-index just run this REPAIR TABLE table_name.
• A fast way to rebuild an index is to use this query: "REPAIR TABLE table_name QUICK;"
Note: You're using the name of the table only, not the name of any indexes. If you have more than one index against the 'table_name' table, all of them will be re-built.