Exchange 2013 authentication fails - "The server is not an ActiveSync server" [answered]

Seems that you have already answered your own Q in the first sentence of the description.."stopped working after .. server was changed from Exchange 2007 to 2013". It shouldn't be a surprise to any that these proprietary service/tech corps like M$ and Google change their closed service APIs w/o a notice and/or caring to announce to apps or devs or clients that rely on these interfaces or access/protocol conventions. There usually is nothing or no easy way for client sw devs or users to stay in sync with these server-side API-changes, specifically because they are done on purpose to make the lives of non-ecosystem or open-based sw to access/use these proprietary/closed services. It's especially the case with Facebook, Whatsapp, even Twitter and others that they want to keep indepedent and open IT communities (users, devs, sw, platforms, OS:s, etc) outside of their vendor-locked closed ecosystem borders. Ofc workarounds for these API changes can be implemented but at great cost and effort by the communities.

Thanks jjaona! Your comment was comforting, yet not very helpful.

Exchange Server Protocol specifications are available here: https://msdn.microsoft.com/en-us/library/cc307725%28v=exchg.80%29.aspx

@Possi - In such cases account recreation is necessary since server keys will be totally different. Jolla does support Exchange protocol 14, so should be fine, please let me know if you still have issues.