Intermittent MySQL 1045 “Access denied for user 'root' 'fd12:…'”

Question

My Railway PHP workers (with infinity loop) lose MySQL auth after \~20 min; same root creds fail with 1045 as internal IPv6 host changes.  
  
{ "where": "runFromIndex", "error": "SQLSTATE$$HY000$$ $$1045$$ Access denied for user 'root'@'fd12:e6a2:5c4e:1:2000:1d:e8b5:de8d' (using password: YES) (Connection: default, SQL: select \* from `automation_steps` where `automation_id` \= 35 order by `step_order` asc)" }  
  
Any help? Thanks.