MV on remote/master table fails to resume syncing (after master db host was temporarily unreachable)
If the controlling scheduled DBMS_JOB job fails, it may need to be manually reset/restarted. If you want more flexibility/resiliency with this, use Oracle Scheduler to control the refresh execution, rather than the default DBMS_JOB. Do this by leaving the start and next portions out of the MV definition:
create materialized view target.wo_mv 
build immediate 
refresh fast 
as (
select
    workorderid
    --other columns
from
    master.workorder@my_dblink         
);  

Then build a Scheduler job with a call to DBMS_REFRESH to refresh your MV:
begin
   dbms_refresh.make(
     name                 =&gt; '15_MINUTE_REFRESH',
     list                 =&gt; '',
     next_date            =&gt; sysdate,
     interval             =&gt; '/*15:mins*/ sysdate + 15/(60*24)',
     implicit_destroy     =&gt; false,
     lax                  =&gt; false,
     job                  =&gt; 0,
     rollback_seg         =&gt; null,
     push_deferred_rpc    =&gt; true,
     refresh_after_errors =&gt; true,
     purge_option         =&gt; null,
     parallelism          =&gt; null,
     heap_size            =&gt; null);
end;
/

begin
   dbms_refresh.add(
     name =&gt; '15_MINUTE_REFRESH',
     list =&gt; 'WO_MV',
     lax  =&gt; true);
end;
/

commit;

Be sure to run all commands as the schema/user which owns the materialized view.
Also see here: https://oracle-base.com/articles/19c/dbms_job-jobs-converted-to-dbms_scheduler-jobs-19c#mview-refresh-groups