I am also having this issue. I've changed my password, still got the error. Deleted cookies and cache, still no luck. I have emailed support twice, no reply. Will we encounter issues using our programs after the maintenance on the 18th? 

Hello Shelley Van Eindhoven and NBIS Bookkeeper

Thanks for reaching out. Please see this post regarding "Authentication Error - EC02" with suggested steps to try. If clearing cache and cookies doesn't help, try the following steps reworded below:
1. Attempt to login
2. Check the URL of the authentication error page, it likely is: mysageone.na.sageone.com/.../error-id-provider 
3. If you remove /errors/error-id-provider from the end of the URL you should be able to login normally.

You can also reach the support team directly by chat here.

Warm Regards, 
Erzsi

Thanks, but that didn't work either. And I'm still getting the error. Thankfully, it appears my program is working ok after the maintenance, but it is still something needing to get resolved.

Im having the issue as well and the only work around is trying another browser

Hi Michael, thanks for reaching out. I've forwarded your comment onto the Sage Accounting support team to see what other insights they might have for resolving the error.

I've been using Google Chrome. After seeing Michael's comment, I tried using Microsoft Edge. I still have the error. No luck either way.

Hello everyone,

I wanted to share that we've published a new article specifically addressing the "Authentication Error EC02" that some of you have encountered. This article provides a comprehensive guide on how to resolve this issue, with updated and simplified steps that can help you gain access to your Sage services without hassle.

For those looking for immediate solutions to the EC02 error, particularly when logging into Sage Accounting or other cloud-based software through www.sage.com, I highly recommend checking out this new resource. 

You can find the article here: Solving Authentication Error EC02

Should you have any further questions or require additional assistance, please don't hesitate to reach out.

Warm Regards,
Erzsi