I am on Version 6.5.7 of WinSCP. I upgraded after a previous version kept failing to connect.
The error seems to be certificate related. The log is showing this:
[2026-09-30 15:02:09.958] [2398] TLS failure: Certificate not trusted. (8)
[2026-09-30 15:02:09.958] [2398] Hostname: winscp.net, Certificate: XXXXX
[2026-09-30 15:02:09.990] [2398] Error from Windows certificate store: Error: 800B0109 (A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider), Chain index: 0, Element index: -1
[2026-09-30 15:02:09.990] [2398] Root certificate: XXXXX
[2026-09-30 15:02:09.990] [2398] TLS certificate error: Certificate not trusted.
[2026-09-30 15:02:09.990] [2398] HTTP request failed: Certificate not trusted.
Error: 800B0109 (A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider), Chain index: 0, Element index: -1
Server certificate verification failed: issuer is not trusted
[2026-09-30 15:02:09.990] [2398] Certificate error detected.
I've seen other posts on this forum about this, but not sure what the solution is to get this working?