Hello :

I am having a same issue.

SSRS 2012 upgraded from SSRS 2005 few years ago.

<httpRuntime maxRequestLength="1048576" executiontimeout="10800" />

I checked the web.config file and it is set to 1048576. much beyond the 655267 value mentioned by someone. ( 64 MB hard limit)

I get this error when I try to create a new or edit an existing subscription .

Maximum request length exceeded.

I am seeing this error only now.

Existing subscriptions seem to be running fine.

Any help is appreciated.