Users cannot register work in JIRA Trock

Good Morning. For now 4 users cannot register work in JIRA Trock as they get this error message. I don't know what the reason could be but I'm sure that in the next few days more users will have the same problem. Please help. Thank you. * I am using the Jira version (v7.13.11) * The Trock versión is 2.6.4