Do you have a web browser extension for Strava? Those can cause this if the extension makes to much requests in a short time.

I've had the same problem since yesterday. In the APP and in a browser.

I have not implemented any interfaces. I only create my comments manually.

Does anyone have a solution?

This cause has already been mentioned above as a possible cause.
I have checked this: I am not using a browser extension.

I’m having the same problem on the app and it won’t let me comment bc of rate limit exceeded…. Any other ideas? 

after a discussion with support, i had to wait 24 hours. now it works.
I can't say whether the wait was the solution or whether support fixed something.

I'm just returning to this forum and the Strava API in general. I thought that 3rdy party integrators need to implement our own backend message queue that aggregates individual user requests into bulk requests made to the Strava API. Do you know what your request limit is, within a 15 minute timespan?

I've just started getting this message and I am using the Strava Mobile App!  Closed it down and reopened it and still giving me issues

It was prob both. 

I’m having the same issue and it’s happened before. Usually due to too many comments on the feed. If I have a lot of friends running races together or doing big events, I comment a lot. Now my activities aren’t even getting uploaded. @StravaSupport needs to do something about this. Also prob only affects the free users.