You say you're using a UNI-T UT61E meter which, according to its manual, is a 22000 count meter with 1.2% basic accuracy + 10 counts of error on the 750 VAC range, which is the one the meter would use for that measurement. This comes from page 48 of that manual.
Although that meter claims to be a 22000 count meter, it is only that good on the lower ranges. It only has 0.1 V resolution on the 750 V range, which effectively makes it a 7500 count meter on that range.
That resolution spec means the reading could be off by as much as 1 V and still be in-spec by that error source alone. But the bulk of the error comes from the basic accuracy spec, which adds up to another 1.2% of the measurement to the error spec, or 2.88 V in this case. That means your meter would still be in-spec if it gave a value ±3.88 V of the correct value.
Given the 230 V ±10% value from other answers, your wall voltage could be as high as 253 V, while your meter's error could only be as much as 244 V, rounded off. That means your wall power is within its proper range, unless your meter is very badly out-of-spec.