We experienced login issues for users created (or updated) between September 2 and September 13.
These errors were caused due to some sanitization errors in data between preparing for this weekend's migration (September 2) and the actual migration (September 13, see https://status.getsilverfin.com/incidents/nbqx4btpwq1k)..)
We sincerely apologize for any inconvenience this caused and want to stress that all data was safe at all times. Any missing data has now been put right, and all logins should work as expected.
Finally, we will look into improving our maintenance processes.