while upgrading ise 2.1 to 2.6 getting "Could not connect to new deployment Primary as its certificate is not trusted or valid. Import the valid https certificate of the same to current Primary node's certificate store." error

[sapednek]

While upgrading ise 2.1 to 2.6 getting "Could not connect to new deployment Primary as its certificate is not trusted or valid. Import the valid https certificate of the same to current Primary node's certificate store." error

[hslai]

Please try what suggested. If not helping, engage Cisco TAC to troubleshoot further.