Unable to upload vtt files in Drupal 8

Description

Getting an error "File Type isn't allowed" when uploading VTT files in Drupal 8.

Issue is reported here: https://h5p.org/node/658870/

This is not related to https://h5ptechnology.atlassian.net/browse/HFP-2879 since the issue is also present even with the file extension on lower case.

Environment

Drupal 8.7.7
H5P 8.x-1.0-rc17

Acceptance Criteria

None

Status

Assignee

Unassigned

Reporter

Bienvenido Villadelrey

Labels

None

Funding

None

Code reviewer

None

Released

None

Time tracking

0m

Fix versions

None

Sprint

None

Priority

Medium
Configure