I am in the process of migrating issues from .CSV to JIRA Cloud instance using 'External System Import' facility. At times, the import runs successfully, however many a times after mapping all the .csv file fields with JIRA fields when I proceed to next screen it displays 'Contact Atlassian' message and at times throws '404 error'.
Today, importing of 40 issues in JIRA had taken more than an hour and is still in progress (still 75%.....). Since I am following the same steps which I did for previous modules, taking so much time is not acceptable as it is impacting the migration timelines shared with our client.
Requesting to please advise on the same.