Nice language model you have there, would be nicer if it could also search the web in addition to providing unhelpful advice.
forums post: [SOLVED] Search messages with URL keyword returns no results found
github issue: Search does not find words in URL's · Issue #5786 · mattermost/mattermost · GitHub
atlassian: [MM-1082] - Mattermost
Seems like nobody wants to actually fix this in the foreseeable future. Which is fine, but for some users this is an important feature, so it should be emphasized in the documentation that the (recommended) PostgreSQL DB has this known bug. Afaik no other DB type is currently recommended / supported, so there are no good solutions or workarounds.