How are you getting it to work on MRR properly?
For me, it connects fine and mines to my pool ok but if the renters' pool is not compatible or something it stops hashing. MRR refunded the renter twice in a short time. I contacted MRR for advice but all they literally said was "please ensure you have allpools enabled", which obviously isn't possible when you don't have access to the command line.
I haven't run into such issues yet. If the renter's pool is not compatible then I don't think there is anything you can do but that would be a problem between MRR and the renter. Make it clear to MRR that you're using the E3. You might want to check the logs on the miner to see if there is anything that would help MRR debug the issue.
"allpools" is for claymore devfee, not relevant here. Claymore miner would stop if it can't mine the fee, which is probably what they're referring to.